Evaluation of Streptococcus pneumoniae as a cause of acute otitis media in Colombia: A prospective study

Wilfrido Coronell-Rodriguez; Rosanna Camerano; Juan Carlos Alvarado-Gonzalez; Alejandra Puerto; Josefina Zakzuk; Nelson R Alvis-Zakzuk; Lina Moyano-Tamara; Sebastian Medina; Claudia Beltran; Maria Betancur; Monica Rojas; Luis Enrique Farias; Hernando Pinzon-Redondo; Perla Villamor; Steven Osorio; Nelson Alvis-Guzmán

doi:10.1371/journal.pone.0326660

. 2025 Jul 28;20(7):e0326660. doi: 10.1371/journal.pone.0326660

Evaluation of Streptococcus pneumoniae as a cause of acute otitis media in Colombia: A prospective study

Wilfrido Coronell-Rodriguez ¹, Rosanna Camerano ², Juan Carlos Alvarado-Gonzalez ^1,^2,³, Alejandra Puerto ^1,², Josefina Zakzuk ¹, Nelson R Alvis-Zakzuk ^2,⁴, Lina Moyano-Tamara ², Sebastian Medina ⁵, Claudia Beltran ⁵, Maria Betancur ⁵, Monica Rojas ⁵, Luis Enrique Farias ⁵, Hernando Pinzon-Redondo ^1,³, Perla Villamor ³, Steven Osorio ^1,^3,⁶, Nelson Alvis-Guzmán ^2,^7,^*

Editor: Luis Felipe Reyes⁸

¹Universidad de Cartagena, Cartagena, Colombia

²ALZAK, Cartagena, Colombia

³Hospital Infantil Napoleón Franco Pareja, Cartagena, Colombia

⁴Institución Universitaria Mayor de Cartagena, Cartagena, Colombia

⁵MSD, Bogotá, Colombia

⁶Hospital Serena del Mar, Cartagena, Colombia

⁷Universidad de la Costa, Barranquilla, Colombia

⁸Universidad de La Sabana, COLOMBIA

Competing Interests: This study was funded by MSD Colombia, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA. Claudia Beltran, Sebastian Medina, Monica Maria Rojas, Maria Alejandra Betancur and Luis Enrique Farias are MSD employees. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

^✉

* E-mail: nalvis@cuc.edu.co

Roles

Wilfrido Coronell-Rodriguez: Conceptualization, Methodology, Validation, Writing – original draft, Writing – review & editing

Rosanna Camerano: Data curation, Formal analysis, Visualization, Writing – original draft, Writing – review & editing

Juan Carlos Alvarado-Gonzalez: Data curation, Formal analysis, Validation, Visualization, Writing – original draft, Writing – review & editing

Alejandra Puerto: Methodology, Validation, Writing – review & editing

Josefina Zakzuk: Conceptualization, Methodology, Writing – original draft, Writing – review & editing

Nelson R Alvis-Zakzuk: Conceptualization, Methodology, Project administration, Supervision, Writing – original draft, Writing – review & editing

Lina Moyano-Tamara: Formal analysis, Project administration, Supervision, Writing – original draft, Writing – review & editing

Sebastian Medina: Funding acquisition, Methodology, Project administration, Supervision, Writing – review & editing

Claudia Beltran: Funding acquisition, Methodology, Project administration, Supervision, Writing – review & editing

Maria Betancur: Funding acquisition, Methodology, Project administration, Supervision, Writing – review & editing

Monica Rojas: Funding acquisition, Methodology, Project administration, Supervision, Writing – review & editing

Luis Enrique Farias: Funding acquisition, Methodology, Project administration, Supervision, Writing – review & editing

Hernando Pinzon-Redondo: Resources, Validation, Writing – review & editing

Perla Villamor: Validation, Writing – original draft, Writing – review & editing

Steven Osorio: Validation, Writing – original draft, Writing – review & editing

Nelson Alvis-Guzmán: Conceptualization, Methodology, Writing – original draft, Writing – review & editing

Luis Felipe Reyes: Editor

PMCID: PMC12303261 PMID: 40720527

Abstract

Objective

Since the introduction of the pneumococcal conjugate vaccine PCV-10 in 2011 its impact on acute otitis media (AOM) in children under five years of age in Colombia was unknown. We aimed to describe the clinical and sociodemographic characteristics of a prospective cohort of patients between 3 and 59 months old attending a children’s hospital in Cartagena, Colombia.

Methods

A prospective cohort study was conducted over a 12-month period from August 5^th, 2022 to August 5^th, 2023. Diagnosis of AOM was confirmed by an otorhinolaryngologist. Middle ear fluid samples were obtained by swab or tympanocentesis, depending on the presence of spontaneous drainage. Samples with a positive culture for S. pneumoniae were sent to the Colombian National Health Institute for serotyping. We also estimated the prevalence of AOM caused by S. pneumoniae, the serotype distribution and antimicrobial resistance patterns.

Results

A total of 61 patients were enrolled, 58% were male, the median age was 12 months (IQR: 8–24). The most common isolated microorganisms were Pseudomonas aeruginosa (14.8%), methicillin-resistant Staphylococcus aureus (13.1%), and Streptococcus pneumoniae (9,8%). Six cases of S. pneumoniae were identified, median age was 26.5 months (IQR: 8–45), none had any comorbidities, and only one had a history of previous AOM episodes. Five of them were vaccinated. The serotype distribution was 19A (67%), 10F and 35A (17%) each. Within the antimicrobial resistance patterns, serotype 19A was multidrug resistant (resistance to: beta-lactams, macrolides, lincosamides and TMP/SMX).

Conclusion

S. pneumoniae continues to be a leading cause of AOM in our country. Serotype 19A accounts for 67% of these infections and exhibits a multidrug-resistant pattern similar to that observed in invasive pneumococcal disease. These findings are consistent with international data and provide a baseline for tracking future AOM trends related to S. pneumoniae after the introduction of the PCV-13 vaccine.

Introduction

Acute otitis media (AOM) is a common childhood infection and a leading cause of antibiotic prescriptions [1]. It is estimated that 80% of children experience at least one episode of AOM before the age of three and 50% before the age of one, with a peak occurrence between 9 and 15 months of age [2]. In Latin America, the incidence of AOM ranges from 4.25% to 6.78% [3]. For instance, in a 2016 study published in a Caribbean city in Colombia, the incidence of AOM was found to be 29.4 per 1,000 children [4]. This condition poses significant challenges to public health and health economics, emphasizing the need for effective preventive strategies.

Different pathways are related to AOM development. Although still controversial, bacterial colonization is considered a prerequisite [5–8]. The three most relevant bacterial pathogens reported worldwide are: Streptococcus pneumoniae, responsible for 30% to 50% of all cases [9–11], non-typeable Haemophilus influenzae (15% to 30%), and Moraxella catarrhalis (3% to 20%) [12,13]. In Colombia, similar trends have been observed; the study of Sierra-Lopez et al conducted in Cali reported that the most commonly isolated bacteria in pediatric otitis media cases were H. influenzae (31%) and S. pneumoniae (30%) [14].

Among its complications, otomastoiditis is the most prevalent, although severe conditions such as meningitis and encephalitis have also been documented [15–17]. Middle ear fluid (MEF) analysis plays a critical role in identifying the etiologic agents of AOM. MEF samples provide valuable insights into pathogen prevalence, serotype distribution, and antimicrobial resistance patterns, offering a reliable basis for evaluating the impact of vaccination and guiding therapeutic approaches [18].

Pneumococcal conjugate vaccines (PCV) have been shown to prevent both non-invasive and invasive pneumococcal disease (IPD), including AOM [19–22]. Several studies have reported significant declines in AOM caused by vaccine-included serotypes following the introduction of PCV-7 and PCV-13 in upper-middle-income countries, although non-vaccine serotypes like 19A exhibited replacement effects [20,23,24]. In Colombia, PCV-7 was introduced in 2006 for high-risk children under 2 years of age and its use was expanded in Bogotá in 2008. In 2009, coverage extended to high-mortality regions, and between 2010 in and 2011, PCV13 replaced PCV7 nationwide. In 2011, PCV10 was incorporated into the national immunization program and became universally available in 2012 reaching 89% coverage [25,26]. The introduction of PCV-10 led to an 84.7% national reduction in IPD due to vaccine serotypes in children under five years of age [27,28]. By 2019, national vaccination coverage reached >90% although significant variability was observed among departments; for instance, in Bolívar, S. pneumoniae vaccination historically lagged behind national rates, reaching 80–89% coverage in 2021 [29]. In 2022, PCV-10 was subsequently replaced by PCV-13 [30].

Regarding AOM, a study in Bogotá D.C. and Medellín observed reductions in its incidence following the implementation of PCV-10, consistent with trends reported in other Latin American regions [31]. However, in 2016, an evaluation conducted in Cartagena determined the effectiveness of PCV-10 in a nested case-control study within a cohort of newborns followed up to 18 months of age and found a protection rate of 33% against AOM. The isolated microorganisms were β-lactamase-negative non-typeable H. influenzae (20%), S. pneumoniae (15%), and serotype 6C as the only pneumococcal recognized serotype. Streptococcus pyogenes and Staphylococcus aureus were also isolated, corresponding to 10% of the cases, respectively [32].

Although these findings align with global data on the main etiologic agents of bacterial AOM and serotype distribution trends of S. pneumoniae [13], critical gaps persist in understanding the regional dynamics in Latin America, particularly in Colombia. It is essential to understand the current role of S. pneumoniae in the bacterial etiology of AOM and how the introduction of PCV-10 in infancy impacts the current serotype distribution. The objective of this study was to determine the prevalence of bacterial AOM caused by S. pneumoniae in children aged 3–59 months in a Colombian Caribbean city. The study also aimed to identify S. pneumoniae serotype distribution and antimicrobial resistance patterns from middle ear fluid (MEF) samples. By identifying prevalent serotypes and their antimicrobial resistance, our data can contribute to optimizing antibiotic stewardship and informing the development of regional public health policies aimed at reducing the burden of AOM in children.

Materials and methods

This prospective observational cohort single-center study included children aged 3–59 months diagnosed with AOM who consulted the Napoleon Franco Pareja Children’s Hospital in Cartagena, Colombia. The recruitment period was from August 5, 2022, to August 5, 2023. Fig 1 summarizes the recruitment process and procedures performed for each case included in the study.

Fig 1 — AOM: acute otitis media; ENT: ear, nose, and throat; INS, Colombian National Health Institute.

Ethical considerations

This study was reviewed and approved by the research ethics committee of the Instituto Médico de Alta Tecnología (IMAT) under minute no. 435. All study procedures were implemented in compliance with the Helsinki Declaration. Since participants were underage, written informed consent was obtained from the parent/legal guardian after informing them about the research, in the presence of two witnesses. A copy of the signed and dated consent form was given to the subject before participation in the study (S1 Text). The informed consent adhered to IRB/ERC requirements, applicable laws and regulations. According to Resolution No. 8430 of 1993 of the Colombian Ministry of Health and Social Protection, this study is considered minimum risk [33], since the samples were taken in the context of the medical care of a patient with a clinical diagnosis of AOM and allowed an accurate diagnosis of the etiological agent.

Population and selection criteria

The study included children of both sexes, aged 3–59 months, diagnosed with AOM, who sought consultation at the Napoleón Franco Pareja Children’s Hospital. This hospital is the only pediatric facility in the Colombian Caribbean region that provides comprehensive health services of medium and high complexity to both the contributory (population with ability to pay) and subsidized (population in poverty) regimes of the health system [34].

A two-step evaluation process was used to define eligibility. Suspected AOM cases were initially screened by general physicians. The screening criteria included: 1) moderate or marked bulging of the tympanic membrane (TM), or mild bulging accompanied by marked erythema and reduced or absent mobility, or the presence of cloudy or purulent otorrhea and rupture of a previously intact TM (within 48 hours); and/or 2) signs and symptoms of acute infection, such as otalgia, decreased hearing, fever, lethargy, irritability, anorexia, vomiting, or diarrhea, with onset within the previous 72 hours. Children meeting these criteria were referred for confirmatory evaluation by an otorhinolaryngologist, who established the final diagnosis based on otoscopic findings and the diagnostic standards of the American Academy of Pediatrics (AAP). The presence of systemic symptoms served as supportive evidence but was not sufficient alone to confirm a case [35].

Only children with otorhinolaryngologist-confirmed AOM were assessed against exclusion criteria and subsequently enrolled in the study. Exclusion criteria for participants in this study included: a) having received systemic antibiotic treatment for a disease other than AOM within 72 hours prior to inclusion; b) having received antimicrobial prophylaxis for recurrent AOM; and c) having underlying conditions such as progressive neurological disease, acquired or congenital immunodeficiency, cleft palate, chronic TM perforation, or craniofacial anomalies. Additionally, participants with a history of recurrent AOM, defined as a new episode of AOM occurring 3 weeks after initial diagnosis, were also excluded.

Sample collection

The otorhinolaryngologist evaluated participants who met the inclusion criteria and determined the need for tympanocentesis as a diagnostic and therapeutic procedure in cases with an intact TM using pneumatic otoscopy. In cases of ruptured TM accompanied by spontaneous otorrhea, a swab sample of MEF was taken.

An otorhinolaryngologist performed tympanocentesis under appropriate conditions using a CDT speculum adapted to the patient’s age and with prior administration of topical anesthetic. The sample was labeled and stored in a sterile container with the subject’s identification number, sample site (left or right ear), and date of collection. It was then sent directly to the clinical laboratory at room temperature.

For MEF sampling, the external auditory canal (EAC) was cleaned with a disposable gauze. Subsequently, a sample was taken using a slit head otoscope with a slit for a thin, flexible wire swab, ensuring no contact with the walls of the EAC [36,37]. In cases of bilateral AOM with discharge, the MEF sample was taken from only one ear. The samples were labeled with the subject’s identification number, sample site (left or right ear), and date of collection. They were then sent in Amies medium with activated charcoal directly to the microbiology laboratory at room temperature.

Laboratory analysis

For the cultures, samples were inoculated onto sterile 5% lamb’s blood agar and chocolate agar plates. The plates were then incubated at 37°C in a 5% CO₂ atmosphere for 24 hours. After incubation, the colonies were evaluated for growth.

Colonies that had produced alpha-hemolysis were subjected to Gram staining, followed by catalase and oxidase tests.

Phenotypic tests were performed such as: 1) The optochin test: the strains that showed alpha-hemolysis were inoculated on sheep blood agar in a CO2 incubator (5–10%) and a 5 mg optochin disk was placed and incubated for 18–24 hours at a temperature of 37ºC. After this, the strains were reviewed and those that had an inhibition halo > 14 mm (sensitive to optochin) confirmed the presence of pneumococcus. 2) The other phenotypic test used was bile solubility: The isolated strains were exposed to bile salts, and these were lysed or destroyed, giving a positive bile solubility test.

The identification of the microorganism and its susceptibility profile were performed with automated methods (Microscan Autoscan-4 System Beckman Coulter®, Pasadena, California, United States). Under this system, the MICroSTREP plus® panel was used to identify the microorganism and its susceptibility to different groups of antimicrobials by means of cards with different minimum inhibitory concentration (MIC): beta-lactams (penicillins, cephalosporins and carbapenems), macrolides (erythromycin, azithromycin and clarithromycin), lincosamides (clindamycin), trimethoprim/sulfamethoxazole (TMP/SMX), chloramphenicol, glycopeptides (vancomycin), and oxazolidinones (linezolid) or sensitive (no resistance to any antimicrobial was reported).

S. pneumoniae isolates were prepared in Amies transport medium with activated charcoal and sent to the laboratory of the Colombian National Institute of Health (INS) at a temperature between 18 and 25°C. Serotyping was performed by a phenotypic confirmation method using the capsular swelling test known as the Quellung reaction (Sattens Serum Institute, Copenhagen, Denmark).

Follow-up

Cases positive for S. pneumoniae were followed up with a telephone call after 10 days to evaluate clinical improvement, the need for further consultation due to persistent symptoms, hospitalization, changes in antibiotics, and/or the presence of complications.

Data analysis

The study examined several sociodemographic variables, including age, ethnic group, parental education level, household structure, and potential risk factors such as exposure to tobacco smoke, daycare attendance, and breastfeeding practices. Regarding clinical variables, we collected information on comorbidities, previous episodes of AOM, and pneumococcal vaccination status. We reviewed the vaccination card and checked PAIWEB, an Expanded Plan of Immunization (EPI) tool to manage and monitor citizens’ vaccination history information in the country, which is available at http://www.paiweb.gov.co. We collected all variables of interest using an electronic questionnaire designed on the KoboToolbox® platform.

We estimated the prevalence of AOM caused by S. pneumoniae and the distribution of serotypes. Resistance patterns were identified from the MEF samples collected, based on the classification of antimicrobial groups mentioned in the laboratory analysis section. The number and groups of antimicrobials to which each isolated serotype presented resistance were described in relation to the therapeutic management received and the outcome reported in the follow-up.

Descriptive statistical methods were used to summarize sociodemographic and clinical information. For categorical variables, we calculated measures of absolute and relative frequencies. For quantitative variables, we applied a normality test and calculated measures of central tendency and variability, including mean, standard deviation (SD), median, interquartile range (IQR), and percentiles. As an exploratory analysis, the population-level incidence of AOM due to S. pneumoniae in the population was estimated using as a population base the projected number of children in Cartagena in 2022, as reported by the National Administrative Department of Statistics (DANE), along with the number of AOM cases reported in Cartagena through the Integrated Social Protection Information System (SISPRO), and an extrapolation of the number of cases attributable to S. pneumoniae, based on the prevalence obtained in this hospital-based study. The incidence rate was estimated with 95% confidence intervals. All analyses were conducted using R software version 4.1.2 via the RStudio interface.

Results

During the study period, a total of 82 patients met eligibility criteria through a priority consultation, but only 61 patients had confirmation of AOM diagnosis by an ENT specialist. The latter group formed the study sample (Fig 1). The peak recruitment months were September (n = 12) and October (n = 8) in 2022, and April 2023 (n = 8) (Fig 2).

Fig 2 — The monthly number of cases for each group is showed within bars, whereas the total number of patients recruited per month is showed above each bar.

The median age of the participants (n = 61) was 12 months (IQR = 8.0–24.0), and 35/61 were male (57.4%). All participants belonged to the subsidized healthcare regime. Of these, 38/61 (62.3%) of parents or caregivers had completed high school. The median number of people per household was 4 (IQR = 4–5), and they lived with 1–3 children. In the study, 6/61 (9.8%) of participants were exposed to tobacco smoke, 13/61 (21.3%) attended day care centers, 32/61 (52.5%) used a bottle, and nearly 50% (31/61) were breastfed for 4–6 months. Only one participant reported more than two episodes of AOM (Table 1).

Table 1. Sociodemographic characteristics of patients.

Variable	All patients		AOM patients, microorganism other than S. pneumoniae		AOM patients with S. pneumoniae
	n = 61		n = 55		n = 6
	N	%	n	%	N	%
Sex
Female	26	42.6	22	40.0	4	66.7
Male	35	57.4	33	60.0	2	33.3
Age (months)	Median = 12.0		Median = 12.0		Median = 26.5
Age (months)	IQR [8–24]		IQR [7–24]		IQR [8–45]
Education level
Schooled	12	19.7	9	16.4	3	50
Unschooled	49	80.3	46	83.6	3	50
Education level of parent/caregiver
None	1	1.6	1	1.8	–	–
Elementary school, completed	2	3.3	2	3.6	–	–
Elementary school, not completed	5	8.2	5	9.1	–	–
High school, completed	38	62.3	32	58.2	6	100
High school, not completed	9	14.8	9	16.4	–	–
Technician or technologist, completed	2	3.3	2	3.6	–	–
Technician or technologist, not completed	1	1.6	1	1.8	–	–
University, completed	2	3.3	2	3.6	–	–
University, not completed	1	1.6	1	1.8	–	–
Number of people living in the household	Median = 4.0		Median = 3.0		Median = 4.0
Number of people living in the household	RIQ [4.0–5.0]		RIQ [4.0–5.0]		RIQ [4.0–8.0]
Number of children living in the household	Median = 2.0		Median = 2.0		Median = 2.0
Number of children living in the household	RIQ [1.0–3.0]		RIQ [1.0–3.0]		RIQ [1.0–3.0]
Exposure to cigarette smoke
Yes	6	9.8	6	10.9	0
No	55	90.2	49	89.1	6	100
Attendance to day care
Yes	13	21.3	11	20.0	2	33.3
No	48	78.7	44	80.0	4	66.7
Use of baby feeder/bottle
Yes	29	47.5	26	47.3	3	50
No	32	52.5	29	52.7	3	50
Exclusive breastfeeding
Yes	38	62.3	34	61.8	4	66.7
No	23	37.7	21	38.2	2	33.3
Duration of breastfeeding
< 1 month	6	9.8	5	9.1	1	16.7
1 - 3 months	9	14.8	7	12.7	2	33.3
4 - 6 months	31	50.8	29	52.7	2	33.3
7 - 12 months	8	13.1	8	14.5	0	0
> 12 months	7	11.5	6	10.9	1	16.7

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Regarding breastfeeding practices, 34/55 (61.8%) of infants were exclusively breastfed, with the majority (n = 29/55; 52.7%) being breastfed for 4–6 months. Approximately half of the infants reported the use of a bottle or kettle. In patients with AOM caused by S. pneumoniae, the majority were female (n = 4/6; 66.7%) with a median age of 26.5 months (IQR = 8–45). Of these, 4/6 (66.7%) were exclusively breastfed, and none were exposed to tobacco smoke (Table 1).

Regarding the clinical characteristics of the patients (Table 2), of the 61 patients, 38 (62.3%) received the PCV-10 vaccine, as they were born before April 30, 2022. Twenty (32.8%) received the PCV-13 vaccine, and 3 (4.9%) did not receive any pneumococcal vaccine. Among the unvaccinated patients, one tested positive for S. pneumoniae and presented with clinical complications. Among the six patients with S. pneumoniae isolation, five (83.3%) had received PCV-10, while the remaining case (16.7%) corresponded to the unvaccinated patient mentioned above.

Table 2. Clinical characteristics of patients.

Variable	All patients		AOM patients, microorganism other than S. pneumoniae		AOM patients with S. pneumoniae
	n = 61		n = 55		n = 6
	N	%	n	%	N	%
Previous AOM episodes
0	55	90.2	50	90.9	5	83.3
1	4	6.6	3	5.5	1	16.7
2	1	1.6	1	1.8	–	–
> 2	1	1.6	1	1.8	–	–
Comorbidities
Yes	2	3.3	2	3.6	–
No	59	96.7	53	96.4	6	100
Received antibiotics 30 days before study inclusion
Yes	1	1.6	1	1.8	0	–
No	60	98.4	54	98.2	6	100
Pneumococcal vaccination
Yes	58	95.1	53	96.4	5	83.3
No	3	4.9	2	3.6	1	16.7
Vaccine doses received ^*
1	4	6.9	4	7.5	0
2	33	56.9	31	58.5	2	40
Booster dose	21	36.2	18	3.4	3	60

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Proportion calculated from the total number of vaccinated patients.

Six of the total participants (9.8%) had at least one previous episode of AOM, with five patients belonging to the group of AOM due to microorganisms other than S. pneumoniae and one patient to the group of AOM due to S. pneumoniae. Among the patients, only two had underlying comorbidities. Additionally, 58/61 (95.1%) had received at least one dose of pneumococcal vaccine, and 21/58 (36.2%) had received a booster dose.

Out of the 61 MEF samples collected, S. pneumoniae was isolated in six samples, five of which were collected by swabbing and one by tympanocentesis. This results in an estimated prevalence of 9.8%. Based on the information recorded in SISPRO, the incidence rate of AOM in Cartagena is 11.07 (95% CI 10.1–11.8) per 1,000 infants aged 0–4 years. Based on the frequency of S. pneumoniae obtained in this study, we estimate 1.09 (95% CI 0.86–1.32) cases per 1,000 person-years in this age group [38]. Fig 3 shows that, in addition to commensal microorganisms of the EAC, the most frequently isolated microorganisms were Pseudomonas aeruginosa (n = 9/61; 14.8%), methicillin-resistant S. aureus (n = 8/61;13.1%), and S. pneumoniae (n = 6/61; 9.8%).

Out of the patients infected with S. pneumoniae, five had received the pneumococcal vaccine, while 3/5 (60%) had received a booster dose (Table 2). The patient who had not received the initial dose of the vaccine was a 3-month-old infant (Table 2). Due to the patient’s complex clinical outcome, which included established symptoms of AOM concomitant with otomastoiditis, intravenous antibiotics were required, and tympanocentesis was indicated. The serotype isolated from the MEF in this patient was 19A. In this group of six patients with S. pneumoniae isolation, the identified serotypes corresponded to the non-PCV-10 serotype group. Serotype 19A was the most frequent (n = 4), while serotypes 10F (n = 1) and 35A (n = 1) were also isolated.

Regarding resistance patterns, Fig 4 indicates that all pneumococcal serotypes isolated showed some degree of antimicrobial resistance. Serotype 19A presented resistance to up to four groups of antimicrobials, while serotypes 10F and 35A reported resistance to only one group of antimicrobials.

Follow-up of cases diagnosed with AOM due to S. pneumoniae (Table 3) showed that one patient had recurrence of symptoms and required a change of antibiotic treatment. The other five cases with isolation of S. pneumoniae were effectively treated with first-line antibiotics (i.e., amoxicillin). Intravenous ceftriaxone was used in the patient who required tympanocentesis due to aggressive clinical instauration; however, none of these patients required additional interventions nor had sequelae in the clinical follow-up.

Table 3. Outcome of cases with S. pneumoniae isolation.

Case #	Isolated serotype	Resistance profile	MIC	Antibiotic treatment	Treatment outcome
1	10F	Resistance to chloramphenicol	8	Oral amoxicillin	Symptoms resolution
2	19A	Resistance to cefuroxime, erythromycin, clindamycin, TMP/SMX	8 >4 >2 >2/38	Oral amoxicillin	Symptoms resolution
3	35A	Resistance to TMP/SMX	>2/38	Oral amoxicillin	Symptoms resolution
4	19A	Resistance to erythromycin	>1	Oral amoxicillin	Symptoms resolution
5	19A	Resistance to macrolide and clindamycin	>=1	Oral amoxicillin	Symptoms recurrence
6	19A	Resistance to cefuroxime, erythromycin, TMP/SMX	>8 >4 >2/38	IV ceftriaxone	Complicated with otomastoiditis that responded adequately to treatment

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IV, intravenous

Discussion

This study provides updated microbiological evidence on AOM in infants from a subsidized healthcare population in Cartagena, Colombia during a period of high PCV-10 coverage. Among 61 children with otorhinolaryngologist-confirmed AOM, S. pneumoniae was identified in 9.8% of MEF samples, with serotype 19A being the most frequent. Notably, all pneumococcal isolates corresponded to non-PCV-10 serotypes, and most showed resistance to at least one antibiotic group. These findings highlight serotype replacement and antimicrobial resistance in the post pneumococcal vaccination era, underscoring the need for enhanced surveillance and potentially broader vaccine formulations tailored to local epidemiology.

The low frequency of S. pneumoniae in our study (9.8%) contrasts with the study of Sierra et al conducted in Colombia in 2008, reporting 30% of prevalence, in which only 29% of the children had received the PCV7 vaccine [14]. The reduction aligns with international data showing a decline in pneumococcal AOM, as well as IPD, following the implementation of conjugate vaccines [27]. However, the predominance of serotype 19A (67%) in our findings is consistent with serotype replacement effects observed in Latin America after PCV-10 introduction [39]. This suggests that despite vaccination efforts, non-vaccine serotypes remain an important cause of AOM in older children. Evidence of a similar behavior in Colombia regarding isolates of S. pneumoniae causing IPD was found, wherein 19A and 6C are predominant serotypes [26,29]. Notably, the one unvaccinated child developed a severe complication (otomastoiditis), reinforcing the benefits of vaccination despite serotype shifts. As our study, similar finding and complication was reported in Mexico, wherein the majority of cases of otomastoiditis per month (0.15) occurred in unvaccinated participants [15].

Our results are in agreement with the observation that pneumococcal vaccines cause a replacement effect or selective pressure that change the predominance of circulating serotypes, as evidenced in IPD but also in non-invasive pneumococcal disease [40]. The findings of AOM-causing pneumococcal serotypes not included in PCV-10 (19A, 10F, and 35A) align with serotype replacement trends observed in Latin America post-PCV-10 introduction [39]. In contrast, data from Colombia prior to PCV-10 implementation reported serotypes such as 6B, 14, and 19F as predominant causes of AOM [14]. This trend is consistent with findings from other Latin American countries where serotype 19A emerged following PCV-10 implementation. Similarly, Latin American countries with PCV13 schemes recorded a lower frequency of serotype 19A isolation [39]. Serotype 19A accounted for most of the pneumococcal isolates in our study, which is of concern because of its multidrug resistance pattern [41], which can lead to treatment failures and increased complications [42]. Our finding of cases with resistance to macrolides, clindamycin, and TMP/SMX is consistent with regional reports [29]. It is expected that the introduction of PCV13 would also change the distribution of Spn serotypes (serotype replacement) in Colombia [43]. Therefore, continuous epidemiological surveillance during following years is required to evaluate the effectiveness of the current vaccination strategy.

While S. pneumoniae was one of the main pathogens, the most frequently isolated pathogens were P. aeruginosa (14.8%) and methicillin-resistant S. aureus (13.1%). Surprisingly, no isolates of H. influenzae were found, despite its high prevalence and known resistance [44,45]. The high prevalence of commensal or non-typeable isolates (29.5%) may reflect viral infections as etiological agents. MEF cultures are often negative—up to 47% in confirmed cases— [46]. Simultaneous isolation of respiratory viruses may contribute to the pathogenesis of AOM even without bacterial colonization of the nasopharynx. Therefore, the association between symptoms and viral presence in the ear is often significant [47,48].

Regarding seasonality, two peaks of AOM cases were found (Feb–Apr and Sep–Oct), partially overlapping with acute respiratory infections (ARI) trends in the country, where the highest proportion occurred between June and September [49]. This temporal overlap may suggest an epidemiological link, since ARI tends to preceded AOM by predisposing the middle ear to bacterial superinfection [50]. Therefore, the increase in AOM cases observed after ARI peak periods may reflect this pathophysiological sequence, although our data are not sufficient to confirm a consistent seasonal pattern for bacterial AOM.

As vaccine coverage expands to more serotypes, the replacement effect by non-vaccine serotypes [43] or other microorganisms will continue, as will the antimicrobial pressure due to the indiscriminate use of antibiotics. Among the cases of non-pneumococcal AOM, it was found that 25.5% of the participants received the PCV-13 vaccination schedule. This observation could serve as a baseline for future follow-ups to assess the effect of replacement by other microorganisms and serotypes. Pneumococcal surveillance to non-invasive disease, including serotyping and resistance profiling, is critical for tracking the community-level circulation of multidrug-resistant strains. We acknowledge the development and licensure of newer pneumococcal conjugate vaccines (PCV10-SII, PCV-15 and PCV-20 which offer broader serotype coverage and are under evaluation or currently used in various immunization programs of other countries [51–53], but these vaccines were not yet licensed in Colombia at the time of this study.

This study has several strengths. First, the use of high-quality microbiological techniques and standardized procedures ensured the reliability of our findings. The MEF samples were analyzed using validated laboratory methods, including bacterial cultures, optochin sensitivity testing, and bile solubility testing for pneumococcal identification. Additionally, all laboratory procedures were double-checked and cross-verified between the hospital microbiology laboratory and the Colombian INS, ensuring accuracy and consistency. Finally, strict adherence to sample collection and handling protocols minimized contamination risks and ensured high-quality data. The immunization status of cases was verified in a dual manner: first, in priority consultation and then corroborated by the information available in the electronic media of the Colombian EPI. This allowed for the identification and execution of a descriptive analysis of the patients vaccinated with PCV-10 ten years after its implementation in the country in 2012. These strengths ensure the quality of the results, which contribute to the understanding of the impact of vaccination and decision-making.

However, it is important to note that our study has limitations. It was conducted in a single healthcare institution and may not reflect the distribution of pathogens, or the characteristics of subjects treated at home or in other healthcare settings. The evaluation of outcomes through telephone follow-up of only cases of S. pneumoniae infection did not provide insight into the clinical course of AOM caused by other etiologic agents. This would have allowed for comparisons of resistance patterns and clinical outcomes among the different microorganisms. Due to the low number of cases of AOM and S. pneumoniae infection, there was insufficient statistical power to calculate measures of association between the resistance pattern and recurrence of symptoms and treatment failure. Finally, our results provide a baseline for future larger-scale, multi-center studies and contribute valuable microbiological surveillance data on S. pneumoniae serotypes post-PCV-10 introduction.

Conclusions

This study is relevant to understand the effects of vaccination against S. pneumoniae in Colombia, 10 years after the introduction of PCV-10. The prevalence of AOM due to S. pneumoniae has been reduced, although the most frequently found serotypes are not included in PCV-10. Notably, serotype 19A caused 67% of the isolates and has an MDR pattern. Although this study is not nationally representative, the results are consistent with those of national and international studies. As Colombia transitions from PCV-10 to PCV-13, this study provides a valuable baseline for monitoring changes in serotype distribution and resistance patterns by S. pneumoniae in the context of a non-invasive disease.

Supporting information

S1 Text. Informed consent form.

(DOCX)

pone.0326660.s001.docx^{(38.2KB, docx)}

Acknowledgments

The authors express their gratitude to the administrative and assistance personnel of the Napoleón Franco Pareja Children’s Hospital ‘La Casa del Niño’ for their support and contribution to this research. Special thanks to the group of physicians from the priority consultation and emergency department, as well as the residents of the otorhinolaryngology service, for their assistance in recruiting the patients included in the study. Additionally, we would like to acknowledge the methodological advisors of the project.

Data Availability

Data cannot be shared publicly because of sensitive information. Data are available upon request from the Ethics Committee of IMAT Oncomédica (ONC-CEI-CEI-231-2022) (soporteproyectos@alzak.com.co / comitedeeticaeinvestigaciones@gmail.com) for researchers who meet the criteria for access to confidential data.

Funding Statement

This study was funded by MSD Colombia, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA. Claudia Beltran, Sebastian Medina, Monica Maria Rojas, Maria Alejandra Betancur and Luis Enrique Farias are MSD employees. This did not interfere with the authors' ability to analyze, interpret the data, or prepare the manuscript.

References

1.Gavrilovici C, Spoială E-L, Miron I-C, Stârcea IM, Haliţchi COI, Zetu IN, et al. Acute Otitis Media in Children-Challenges of Antibiotic Resistance in the Post-Vaccination Era. Microorganisms. 2022;10(8):1598. doi: 10.3390/microorganisms10081598 [DOI] [PMC free article] [PubMed] [Google Scholar]
2.Leung DY, Sampson H, Geha R, Szefler SJ. Pediatric allergy: principles and practice E-Book. Elsevier Health Sciences. 2010. [Google Scholar]
3.Coronell-Rodríguez W, Arteta-Acosta C, Alvis-Zakzuk N, Alvis-Guzmán N. Costs of acute otitis media in children in a city of the Colombian Caribbean coast. Biomédica [Internet]. 31 de marzo de 2019 [citado 17 de julio de 2023];39(1):75–87. https://www.revistabiomedica.org/index.php/biomedica/article/view/3784 [DOI] [PubMed] [Google Scholar]
4.Coronell-Rodríguez W, Arteta-Acosta C, Osorio-Anaya S, Hoz FDL, Alvis-Guzman N. Incidence of Acute Otitis Media in the Vaccines Era Against Pneumococcus in a City of the Colombia Caribbean Coast: A Cohort Study. Open Forum Infectious Diseases. 2016;3(suppl_1). doi: 10.1093/ofid/ofw172.654 [DOI] [Google Scholar]
5.Barajas Viracachá NC. Prevalencia de serotipos de Streptococcus pneumoniae y otros gérmenes causantes de otitis media aguda en niños de Latinoamérica. Revisión sistemática de la bibliografía. Arch Argent Pediatría. 2011;109(3):204–12. [DOI] [PubMed] [Google Scholar]
6.Vergison A. Microbiology of otitis media: a moving target. Vaccine. 2008;26 Suppl 7:G5-10. doi: 10.1016/j.vaccine.2008.11.006 [DOI] [PMC free article] [PubMed] [Google Scholar]
7.Pichichero ME. Immunologic dysfunction contributes to the otitis prone condition. J Infect. 2020;80(6):614–22. doi: 10.1016/j.jinf.2020.03.017 [DOI] [PMC free article] [PubMed] [Google Scholar]
8.Gisselsson-Solén M, Henriksson G, Hermansson A, Melhus A. Risk factors for carriage of AOM pathogens during the first 3 years of life in children with early onset of acute otitis media. Acta Otolaryngol. 2014;134(7):684–90. doi: 10.3109/00016489.2014.890291 [DOI] [PubMed] [Google Scholar]
9.Trujillo H, Callejas R, Mejía GI, Castrillón L. Bacteriology of middle ear fluid specimens obtained by tympanocentesis from 111 Colombian children with acute otitis media. Pediatr Infect Dis J. 1989;8(6):361–3. doi: 10.1097/00006454-198906000-00007 [DOI] [PubMed] [Google Scholar]
10.Allemann A, Frey PM, Brugger SD, Hilty M. Pneumococcal carriage and serotype variation before and after introduction of pneumococcal conjugate vaccines in patients with acute otitis media in Switzerland. Vaccine. 2017;35(15):1946–53. doi: 10.1016/j.vaccine.2017.02.010 [DOI] [PubMed] [Google Scholar]
11.Barenkamp SJ, Chonmaitree T, Hakansson AP, Heikkinen T, King S, Nokso-Koivisto J, et al. Panel 4: Report of the Microbiology Panel. Otolaryngol Head Neck Surg. 2017;156(4_suppl):S51–62. doi: 10.1177/0194599816639028 [DOI] [PMC free article] [PubMed] [Google Scholar]
12.Schilder AGM, Chonmaitree T, Cripps AW, Rosenfeld RM, Casselbrant ML, Haggard MP, et al. Otitis media. Nat Rev Dis Primers. 2016;2(1):16063. doi: 10.1038/nrdp.2016.63 [DOI] [PMC free article] [PubMed] [Google Scholar]
13.Mather MW, Drinnan M, Perry JD, Powell S, Wilson JA, Powell J. A systematic review and meta-analysis of antimicrobial resistance in paediatric acute otitis media. Int J Pediatr Otorhinolaryngol. 2019;123:102–9. doi: 10.1016/j.ijporl.2019.04.041 [DOI] [PubMed] [Google Scholar]
14.Sierra A, Lopez P, Zapata MA, Vanegas B, Castrejon MM, Deantonio R, et al. Non-typeable Haemophilus influenzae and Streptococcus pneumoniae as primary causes of acute otitis media in colombian children: a prospective study. BMC Infect Dis. 2011;11:4. doi: 10.1186/1471-2334-11-4 [DOI] [PMC free article] [PubMed] [Google Scholar]
15.Chacon-Cruz E, Lopatynsky EZ. Continuous Effectiveness of Pneumococcal 13-Valent Conjugate Vaccine on Pediatric Pneumococcal Otomastoiditis: Results of 15 Years of Active/Prospective Surveillance in a Mexican Hospital on the Mexico-US Border. Cureus. 2021;13(8):e17608. doi: 10.7759/cureus.17608 [DOI] [PMC free article] [PubMed] [Google Scholar]
16.Ren Y, Sethi RKV, Stankovic KM. Acute Otitis Media and Associated Complications in United States Emergency Departments. Otol Neurotol Off Publ Am Otol Soc Am Neurotol Soc Eur Acad Otol Neurotol. 2018;39(8):1005–11. doi: 10.1097/MAO.0000000000001929 [DOI] [PMC free article] [PubMed] [Google Scholar]
17.Lavin JM, Rusher T, Shah RK. Complications of Pediatric Otitis Media. Otolaryngol Head Neck Surg. 2016;154(2):366–70. doi: 10.1177/0194599815611860 [DOI] [PubMed] [Google Scholar]
18.Kaur R, Fuji N, Pichichero ME. Dynamic changes in otopathogens colonizing the nasopharynx and causing acute otitis media in children after 13-valent (PCV13) pneumococcal conjugate vaccination during 2015-2019. Eur J Clin Microbiol Infect Dis. 2022;41(1):37–44. doi: 10.1007/s10096-021-04324-0 [DOI] [PubMed] [Google Scholar]
19.Ordoñez J, Quitián D. PCN57 Cost-Effectiveness of Venetoclax in Combination with Obinutuzumab in First LINE Chronic Lymphocytic Leukemia in Colombia. Value in Health. 2021;24:S29. doi: 10.1016/j.jval.2021.04.149 [DOI] [Google Scholar]
20.Fortanier AC, Venekamp RP, Boonacker CW, Hak E, Schilder AG, Sanders EA, et al. Pneumococcal conjugate vaccines for preventing acute otitis media in children. Cochrane Database Syst Rev. 2019;5(5):CD001480. doi: 10.1002/14651858.CD001480.pub5 [DOI] [PMC free article] [PubMed] [Google Scholar]
21.de Sévaux JL, Venekamp RP, Lutje V, Hak E, Schilder AG, Sanders EA, et al. Pneumococcal conjugate vaccines for preventing acute otitis media in children. Cochrane Database Syst Rev. 2020;11(11):CD001480. doi: 10.1002/14651858.CD001480.pub6 [DOI] [PMC free article] [PubMed] [Google Scholar]
22.Whitney CG, Farley MM, Hadler J, Harrison LH, Bennett NM, Lynfield R, et al. Decline in invasive pneumococcal disease after the introduction of protein-polysaccharide conjugate vaccine. N Engl J Med. 2003;348(18):1737–46. doi: 10.1056/NEJMoa022823 [DOI] [PubMed] [Google Scholar]
23.Martin JM, Hoberman A, Paradise JL, Barbadora KA, Shaikh N, Bhatnagar S, et al. Emergence of Streptococcus pneumoniae serogroups 15 and 35 in nasopharyngeal cultures from young children with acute otitis media. Pediatr Infect Dis J. 2014;33(11):e286-290. [DOI] [PMC free article] [PubMed] [Google Scholar]
24.de Oliveira LH, Camacho LAB, Coutinho ESF, Martinez-Silveira MS, Carvalho AF, Ruiz-Matus C, et al. Impact and Effectiveness of 10 and 13-Valent Pneumococcal Conjugate Vaccines on Hospitalization and Mortality in Children Aged Less than 5 Years in Latin American Countries: A Systematic Review. PLoS One. 2016;11(12):e0166736. doi: 10.1371/journal.pone.0166736 [DOI] [PMC free article] [PubMed] [Google Scholar]
25.Torres Martinez C, Camacho Moreno G, Patiño Niño J, Coronell Rodríguez W, Leal AL, Gámez G. Pneumococcal diseases in Colombia: epidemiological analysis before and during the universal children immunization against Streptococcus pneumoniae in the light of a vaccine change in 2022. Infect Rev Asoc Colomb Infectol. 2024;28(1):8. https://dialnet.unirioja.es/servlet/articulo?codigo=9365352 [Google Scholar]
26.Camacho-Moreno G, Leal AL, Patiño-Niño J, Vasquez-Hoyos P, Gutiérrez I, Beltrán S, et al. Serotype distribution, clinical characteristics, and antimicrobial resistance of pediatric invasive pneumococcal disease in Colombia during PCV10 mass vaccination (2017-2022). Front Med. 2024;11:1380125. [DOI] [PMC free article] [PubMed] [Google Scholar]
27.Agudelo CI, Castañeda-Orjuela C, Brandileone MCDC, Echániz-Aviles G, Almeida SCG, Carnalla-Barajas MN, et al. The direct effect of pneumococcal conjugate vaccines on invasive pneumococcal disease in children in the Latin American and Caribbean region (SIREVA 2006–17): a multicentre, retrospective observational study. Lancet Infect Dis. 2021;21(3):405–17. [DOI] [PMC free article] [PubMed] [Google Scholar]
28.Severiche-Bueno DF, Severiche-Bueno DF, Bastidas A, Caceres EL, Silva E, Lozada J, et al. Burden of invasive pneumococcal disease (IPD) over a 10-year period in Bogotá, Colombia. Int J Infect Dis. 2021;105:32–9. doi: 10.1016/j.ijid.2021.02.031 [DOI] [PubMed] [Google Scholar]
29.Rodríguez WC, Mora-Salamanca AF, Santacruz-Arias J, Alvarado-Gonzalez JC, Saavedra L, Pinzón-Redondo H. Pediatric invasive pneumococcal disease in Bolívar, Colombia: a descriptive cross-sectional study. Infez Med. 2024;32(4):506–17. [DOI] [PMC free article] [PubMed] [Google Scholar]
30.Programa Ampliado de Inmunizaciones PAI. Lineamientos técnicos y operativos para la transición de la vacuna polisacárida contra el neumococo de PCV10 a PCV13 en Colombia. 2022. https://www.minsalud.gov.co/sites/rid/Lists/BibliotecaDigital/RIDE/VS/PP/ET/lineamiento-tecnico-operativo-transicion-vacuna-polisacarda-contra-neumococo-pcv10-pcv13-colombia-2022.pdf [Google Scholar]
31.Carrasquilla G, Porras-Ramírez A, Martinez S, DeAntonio R, Devadiga R, Talarico C, et al. Trends in all-cause pneumonia and otitis media in children aged <2 years following pneumococcal conjugate vaccine introduction in Colombia. Hum Vaccin Immunother. 2021;17(4):1173–80. doi: 10.1080/21645515.2020.1805990 [DOI] [PMC free article] [PubMed] [Google Scholar]
32.Coronell-Rodríguez W, Arteta-Acosta C, Osorio-Anaya S, Mejia-Bermudez S, Hoz FDL, Alvis-Guzman N. Effectiveness of Pneumococcal Conjugate Vaccine PCV10 in a City of the Colombian Caribbean: Case-Control Study Nested in a Cohort. Open Forum Infectious Diseases. 2016;3(suppl_1). doi: 10.1093/ofid/ofw172.639 [DOI] [Google Scholar]
33.Ministerio de Salud y Protección Social. Resolución 8430 de 1993: por la cual se establecen las normas científicas, técnicas y administrativas para la investigación en salud. 1993. https://www.minsalud.gov.co/sites/rid/Lists/BibliotecaDigital/RIDE/DE/DIJ/RESOLUCION-8430-DE-1993.PDF [Google Scholar]
34.Ministerio de Salud y Protección Social. Afiliación en salud. 2023. https://www.minsalud.gov.co/proteccionsocial/Paginas/afiliacion-en-salud.aspx [Google Scholar]
35.Lieberthal AS, Carroll AE, Chonmaitree T, Ganiats TG, Hoberman A, Jackson MA, et al. The diagnosis and management of acute otitis media. Pediatrics. 2013;131(3):e964-99. doi: 10.1542/peds.2012-3488 [DOI] [PubMed] [Google Scholar]
36.Fekete S, Juhász J, Makra N, Dunai ZA, Kristóf K, Ostorházi E, et al. Characterization of middle ear microbiome in otitis media with effusion in Hungarian children: Alloiococcus otitidis may potentially hamper the microbial diversity. Heliyon. 2024;10(21):e39380. doi: 10.1016/j.heliyon.2024.e39380 [DOI] [PMC free article] [PubMed] [Google Scholar]
37.Marchisio P, Esposito S, Picca M, Baggi E, Terranova L, Orenti A, et al. Prospective evaluation of the aetiology of acute otitis media with spontaneous tympanic membrane perforation. Clin Microbiol Infect. 2017;23(7):486.e1-486.e6. doi: 10.1016/j.cmi.2017.01.010 [DOI] [PubMed] [Google Scholar]
38.Departamento Administrativo Nacional de Estadística (DANE). Proyecciones de población [Internet]. Disponible en: https://www.dane.gov.co/index.php/estadisticas-por-tema/demografia-y-poblacion/proyecciones-de-poblacion [Google Scholar]
39.Moreno J, Duarte C, Cassiolato AP, Chacón GC, Alarcon P, Sánchez J, et al. Molecular characterization of Latin American invasive Streptococcus pneumoniae serotype 19A isolates. Vaccine. 2020;38(19):3524–30. doi: 10.1016/j.vaccine.2020.03.030 [DOI] [PubMed] [Google Scholar]
40.Zissis NP, Syriopoulou V, Kafetzis D, Daikos GL, Tsilimingaki A, Galanakis E, et al. Serotype distribution and antimicrobial susceptibility of Streptococcus pneumoniae causing invasive infections and acute otitis media in children. Eur J Pediatr. 2004;163(7):364–8. doi: 10.1007/s00431-004-1447-4 [DOI] [PubMed] [Google Scholar]
41.Instituto Nacional de Salud. Vigilancia por laboratorio de Streptococcus pneumoniae en Colombia, 2016-2021. Instituto Nacional de Salud. 2021. https://www.ins.gov.co/BibliotecaDigital/vigilancia-por-laboratorio-de-streptococcus-pneumoniae-en-colombia-2016-2021.pdf [Google Scholar]
42.Hausdorff WP, Siber G, Paradiso PR. Geographical differences in invasive pneumococcal disease rates and serotype frequency in young children. Lancet. 2001;357(9260):950–2. doi: 10.1016/S0140-6736(00)04222-7 [DOI] [PubMed] [Google Scholar]
43.Løchen A, Croucher NJ, Anderson RM. Divergent serotype replacement trends and increasing diversity in pneumococcal disease in high income settings reduce the benefit of expanding vaccine valency. Sci Rep. 2020;10(1):18977. [DOI] [PMC free article] [PubMed] [Google Scholar]
44.Gatti B, Ramírez Gronda G, Etchevarría M, Vescina C, Varea A, González Ayala SE. Aislamiento de distintos serotipos de Haemophilus influenzae en muestras profundas de pacientes pediátricos. Rev Argent Microbiol. 2004;36:20–3. [PubMed] [Google Scholar]
45.Fuentes Gort K, Tamargo Martínez I, Toraño Peraza G. Susceptibilidad antimicrobiana en cepas de Haemophilus influenzae no tipables aisladas en niños sanos. Rev Cuba Med Trop. 2004;56(2):139–4. [PubMed] [Google Scholar]
46.Falup-Pecurariu O, Leibovitz E, Mercas A, Bleotu L, Zavarache C, Porat N, et al. Pneumococcal acute otitis media in infants and children in central Romania, 2009-2011: microbiological characteristics and potential coverage by pneumococcal conjugate vaccines. Int J Infect Dis. 2013;17(9):e702-6. doi: 10.1016/j.ijid.2013.02.002 [DOI] [PubMed] [Google Scholar]
47.Chonmaitree T. Viral and bacterial interaction in acute otitis media. Pediatr Infect Dis J. 2000;19(5 Suppl):S24-30. doi: 10.1097/00006454-200005001-00005 [DOI] [PubMed] [Google Scholar]
48.Ruohola A, Pettigrew MM, Lindholm L, Jalava J, Räisänen KS, Vainionpää R, et al. Bacterial and viral interactions within the nasopharynx contribute to the risk of acute otitis media. J Infect. 2013;66(3):247–54. doi: 10.1016/j.jinf.2012.12.002 [DOI] [PMC free article] [PubMed] [Google Scholar]
49.Sistema Integrado de Información de la Protección Social. https://www.sispro.gov.co/Pages/Home.aspx. 2023 October 1. [Google Scholar]
50.Paul CR, Moreno MA. Acute Otitis Media. JAMA Pediatr. 2020;174(3):308. doi: 10.1001/jamapediatrics.2019.5664 [DOI] [PubMed] [Google Scholar]
51.Serrano-Mayorga CC, Ibáñez-Prada ED, Restrepo-Martínez JM, Garcia-Gallo E, Duque S, Severiche-Bueno DF. The potential impact of PCV-13, PCV-15 and PCV-20 vaccines in Colombia. Vaccine. 2024;42(7):1435–9. [DOI] [PubMed] [Google Scholar]
52.Ilic A, Tort MJ, Cane A, Farkouh RA, Rozenbaum MH. The Health and Economic Effects of PCV15 and PCV20 During the First Year of Life in the US. Vaccines (Basel). 2024;12(11):1279. doi: 10.3390/vaccines12111279 [DOI] [PMC free article] [PubMed] [Google Scholar]
53.Choi YH, Bertran M, Litt DJ, Ladhani SN, Miller E. Potential impact of replacing the 13-valent pneumococcal conjugate vaccine with 15-valent or 20-valent pneumococcal conjugate vaccine in the 1 + 1 infant schedule in England: a modelling study. Lancet Public Health. 2024;9(9):e654–63. doi: 10.1016/S2468-2667(24)00161-0 [DOI] [PubMed] [Google Scholar]

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All PLOS journals now require all data underlying the findings described in their manuscript to be freely available to other researchers, either 1. In a public repository, 2. Within the manuscript itself, or 3. Uploaded as supplementary information. This policy applies to all data except where public deposition would breach compliance with the protocol approved by your research ethics board. If your data cannot be made publicly available for ethical or legal reasons (e.g., public availability would compromise patient privacy), please explain your reasons on resubmission and your exemption request will be escalated for approval.

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

Reviewer #1: Partly

Reviewer #2: Yes

**********

2. Has the statistical analysis been performed appropriately and rigorously? -->?>

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Have the authors made all data underlying the findings in their manuscript fully available??>

The PLOS Data policy

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #1: Yes

Reviewer #2: Yes

**********

Reviewer #1: This is an interesting paper entitled: Evaluation of Streptococcus pneumoniae as a cause of acute otitis media in Colombia: a prospective study. I want to thank the authors for their efforts in researching pneumococci. Even when the paper is well-written and has some important information, in my scope, it looks like a mix of information in different sections. The manuscript has some major aspects that must be addressed before your work is ready for publication. Grammatically it is well-written and understandable. However, it lacks an organized structure; some sections are very long and lose a common thread. A major restructure, and a new version of the discussion is needed.

Structure:

Please number the lines of the document to make it easier to track sentences that need changes or improvements.

Authors Contribution: use the author’s initials for each section

Introduction:

The introduction looks very long and should be reorganized, with a maximum structure of 3 or 4 paragraphs. In some parts, authors seem to be throwing out ideas for discussion about the subject matter, but they are not argued and remain as free sentences. The number of paragraphs of less than 10 lines hinders the reader from jumping to ideas. Provide more information about MEF and its used in previous studies

The initial sentence in paragraph 4 should be modified. Also, reference number 4 does not support the sentence; there are many different pathways related to the development of SPN AOM. SPN colonization is considered a prerequisite, but there is some controversial data in this regard.

Paragraph 5 does not include meningitis as a complication; relevant data about SPN AOM igniting invasive pneumococcal disease is available. this paragraph is weak; it lacks data on vaccination, vaccination coverage, and circulating serotypes. Colombian literature on these topics has been written by authors such as Severiche et al. and Serrano et al.

Paragraph 6 mentioned several studies, but the references do not match. You should revise the metanalysis in this regard. There is so much information in children rather than in adults. The section that refers to the SPN capsular switch needs more data and support.

Paragraph 7, please include the rates of effective vaccination in Colombia with the previous two vaccines. To provide background information to the reader about which vaccine provided “protection” while the study was being performed.

Paragraph 8: Please provide the numbers for the decrease in incidence.

Methods

Please provide clear information about the type of study. Is this a monocentric study? (provide a line saying so )

What kind of guidelines were followed to perform a study on children? Please provide some lines in the first paragraph of methods standing the Helsinki declaration, the informed consent process, and the approval of an ethical committee. Consider moving the ethical considerations section after the first paragraph as this is a study performed in children.

As tympanocentesis is an invasive procedure with several risks, I would like the authors to provide supplemental information a copy of the informed consent.

It is important to include in figure 1 the number of patients screened

How did the authors avoid reporting a false SPN such as Streptococcus pseudonemoniae, which usually shows alpha hemolysis halo and sensitivity to optokine?

how was the value of patients to be included estimated?

Results

There is a typo in the first paragraph of results (after ... April 2023…)

Only 6 SPN cases among 61 patients were recruited. What was the etiology for the other 55 ?

There are several typos repeatedly in the results “(Error! Reference source not found.)”

I suggest that the authors review the reporting structure of the results, use simple numerators and denominators when referring to percentages to make it easier to read, e.g. : XX/XX (XX%)

Discussion

It is ambitious to say that this single-center study of 62 patients describes the effect of vaccination in children suffering from otitis when 1 in 4 children who consult for this possible diagnosis. Likewise, it is estimated that 40% of the consultations are for AOM in children, and this cut-off seems small and even more so when it is mentioned that the hospital where it was carried out is the one that provides the most care to patients from both the private and public sectors.

The discussion must be reorganized and reformulated. The aspects to be discussed should be contrasted with external or internal data previously found before the PCV-10 vaccine introduction.

The strengths of the study should be focused on supporting the results by using high-quality techniques, standard procedures, and double-checked test were performed, not in the team training.

Best wishes , look forward to see a new version of your work !

Reviewer #2: I find this article very interesting, as it contributes to the understanding of the epidemiology of pneumococcus as a cause of acute otitis media in Colombia.

In the introduction, the sentence: “In Latin America, the incidence of AOM ranges from 4.25% to 6.78% [2]. In a 2016 study published in a Caribbean city in Colombia, the incidence of AOM was found to be 29.4% per 1,000 children [3]. This poses a challenge for public health and health economics”

It is recommended that the values be presented in the same units to facilitate comparison, either as percentages or as rates per 1,000 children. Review the text "29.4% per 1,000 children," as the "%" sign is unnecessary.

In the introduction, review the sentence: “during the early introduction of PCV-7/PCV-13 (2003-2005), and in the late period after the introduction of PCV-7/PCV-13 (2006-2009)”.

PCV13 was not available during those time periods.

In the introduction, review the sentence: “In Colombia, the PCV-7 vaccine (Prevnar®) was introduced in the Expanded Program on Immunization (EPI) in Bogotá D.C. in 2009 with a '2+1' schedule at 2, 4, and 12 months of age. It was implemented throughout the country during 2010 and 2011”.

Other studies report different dates for the implementation of PCV7 in Colombia: “In Colombia, vaccination against pneumococcus began in 2006 with PCV7, initially targeting children under 2 years of age at high risk of IPD. Since 2008, the vaccine was administered universally initially in Bogotá, and since 2009 it was extended to the departments of Colombia with the highest mortality from acute respiratory infection. In the 2010–2011 period, given the withdrawal of PCV7 from the market, PCV13 was administered in Bogotá and in the higher risk departments”. Ref: Camacho-Moreno G, Leal AL, Patiño-Niño J et al. Serotype distribution, clinical characteristics, andantimicrobial resistance of pediatric invasive pneumococcal disease in Colombia during

PCV10 mass vaccination (2017–2022). Front. Med 2024, 11:1380125.doi: 10.3389/fmed.2024.1380125.

The implementation dates of PCV10 and PCV13 are the same as those reported in other studies from Colombia.

In results: A total of 61 patients were included in the study. How many cases of otitis media occurred in the hospital during the study period? What proportion of patients who presented with AOM were included in the study?

Figure 1 indicates that 82 patients were candidates; I recommend including this information in the main text.

In results delete the phrases: “Error! Reference source not found.Error! Reference source not found”

I recommend describing in the results the type of pneumococcal vaccine received by the 5 patients who were vaccinated. The phrase: “Of the six cases with S. pneumoniae isolation, five had received PCV-10 given that they were born before April 30, 2022” in the discussion should be moved to the results section.

It is also recommended to describe, in the results section, the vaccines used in patients who experienced non-pneumococcal otitis.

How many patients had negative cultures? In table 2 "55 AOM patients, microorganism other than S. pneumoniae," suggesting that all cultures were positive and in Figure 3, the culture results are described, and it indicates that all cases had microbiological isolation, 18 had microbiome of the external auditory canal. However, the discussion states, "In 37% of the cultures, there was no bacterial growth, a finding similar to our study." Review this phrase.

In results the phrase: “Regarding resistance patterns, Figure indicates that all pneumococcal serotypes isolated showed some degree of antimicrobial resistance” Add the corresponding figure number.

Table 3. Clarify whether the beta-lactam resistance is to penicillin and/or ceftriaxone. If resistant to penicillin or ceftriaxone, it is advisable to report the MIC.

In the discussion section the phrase: “who received PCV-10 previously In addition” Add a period after previously.

In the discussion section the phrase: “The findings of AOM-causing pneumococcal serotypes not included in PCV-10 (19, 10F and 35)” The serotype is 19ª

In the discussion section the phrase: “Our study found that the samples exhibited a resistance pattern consistent with what has been described in the literature. This included resistance to macrolides, clindamycin, TMP/SMX, and aminoglycosides” Pneumococcus is intrinsically resistant to aminoglycosides.

**********

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Reviewer #1: No

Reviewer #2: Yes: German Camacho-Moreno

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PLoS One. 2025 Jul 28;20(7):e0326660. doi: 10.1371/journal.pone.0326660.r002

Author response to Decision Letter 1

13 Mar 2025

Luis Felipe Reyes, MD, MSc. PhD

Academic editor

PLOS ONE

Dear Dr. Reyes and reviewers,

Thank you for your comments and valuable suggestions. We are sure that those have allowed us to improve our manuscript considerably. The modifications introduced in the manuscript were done as required. All recommendations were implemented and are highlighted in red throughout the text. Detailed responses to the journal requirements and reviewer's comments are presented as follows:

Journal requirements:

R/ Thank you. We have reviewed PLOS ONE's style requirements and have adjusted the manuscript to conform to them.

R/ Funding information was removed from the manuscript

3. Please state what role the funders took in the study. If the funders had no role, please state: "The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript." If this statement is not correct you must amend it as needed. Please include this amended Role of Funder statement in your cover letter; we will change the online submission form on your behalf.

R/ This study was funded by MSD Colombia, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA. Claudia Beltran, Sebastian Medina, Monica Maria Rojas, Maria Alejandra Betancur and Luis Enrique Farias are MSD employees. This did not interfere with the authors' ability to analyze, interpret the data, or prepare the manuscript.

We updated the cover letter considering this new statement.

4. We note that one or more of the authors are employed by a commercial company: Merck Sharp & Dohme Corp.

A. Please provide an amended Funding Statement declaring this commercial affiliation, as well as a statement regarding the Role of Funders in your study. If the funding organization did not play a role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript and only provided financial support in the form of authors' salaries and/or research materials, please review your statements relating to the author contributions, and ensure you have specifically and accurately indicated the role(s) that these authors had in your study. You can update author roles in the Author Contributions section of the online submission form. Please also include the following statement within your amended Funding Statement. “The funder provided support in the form of salaries for authors [insert relevant initials], but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.” If your commercial affiliation did play a role in your study, please state and explain this role within your updated Funding Statement.

B. Please also provide an updated Competing Interests Statement declaring this commercial affiliation along with any other relevant declarations relating to employment, consultancy, patents, products in development, or marketed products, etc. Within your Competing Interests Statement, please confirm that this commercial affiliation does not alter your adherence to all PLOS ONE policies on sharing data and materials by including the following statement: "This does not alter our adherence to PLOS ONE policies on sharing data and materials.” (as detailed online in our guide for authors http://journals.plos.org/plosone/s/competing-interests). If this adherence statement is not accurate and there are restrictions on sharing of data and/or materials, please state these. Please note that we cannot proceed with consideration of your article until this information has been declared. Please include both an updated Funding Statement and Competing Interests Statement in your cover letter. We will change the online submission form on your behalf.

A. Thank you for this commentary. We already provided and amended the Funding Statement, as follows: “This study was funded by MSD Colombia, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA. Claudia Beltran, Sebastian Medina, Monica Maria Rojas, Maria Alejandra Betancur and Luis Enrique Farias are MSD employees. This did not interfere with the authors' ability to analyze, interpret the data, or prepare the manuscript.”

B. Thanks for your suggestion. We provided an updated Competing Interests Statement, as follows: “This study was funded by MSD Colombia, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA. Claudia Beltran, Sebastian Medina, Monica Maria Rojas, Maria Alejandra Betancur and Luis Enrique Farias are MSD employees. This does not alter our adherence to PLOS ONE policies on sharing data and materials”

5. In the online submission form, you indicated that “Data cannot be shared publicly because of sensitive information. Data will be shared upon request.” All PLOS journals now require all data underlying the findings described in their manuscript to be freely available to other researchers, either 1. In a public repository, 2. Within the manuscript itself, or 3. Uploaded as supplementary information. This policy applies to all data except where public deposition would breach compliance with the protocol approved by your research ethics board. If your data cannot be made publicly available for ethical or legal reasons (e.g., public availability would compromise patient privacy), please explain your reasons on resubmission and your exemption request will be escalated for approval.

R/ We appreciate your commentary in terms of the PLOS data policy. However, sharing the information in a public repository could jeopardize informed consent approved by the Ethics Committee of IMAT Oncomédica (ONC-CEI-CEI-231-2022). Explicitly the informed consent says: “I have also been informed that the tests and procedures will be performed by expert personnel, will be at no cost to me, and their results will be confidential”, which implies that if we potentially share the database, we will be braking the agreement stablished with the patients and their families.

The above support the journal policy which stablish that “This policy applies to all data except where public deposition would breach compliance with the protocol approved by your research ethics board”.

R/ Thank you for this suggestion. We included the ORCID ID of the corresponding author in the online form. https://orcid.org/0000-0001-9458-864X ORCID NELSON ALVIS GUZMAN

7. Please ensure that you refer to Figures 2-4 in your text as, if accepted, production will need this reference to link the reader to the figure.

R/ Thank you, all figures are referenced in the manuscript.

R/ Thank you, all figures and tables were double checked in order to ensure correctly reference into the manuscript.

Reviewers' comments:

Reviewer #1

Manuscript format and Material

1. This is an interesting paper entitled: Evaluation of Streptococcus pneumoniae as a cause of acute otitis media in Colombia: a prospective study. I want to thank the authors for their efforts in researching pneumococci. Even when the paper is well-written and has some important information, in my scope, it looks like a mix of information in different sections. The manuscript has some major aspects that must be addressed before your work is ready for publication. Grammatically it is well-written and understandable. However, it lacks an organized structure; some sections are very long and lose a common thread. A major restructure, and a new version of the discussion is needed.

R/ Thank you for your valuable feedback on our manuscript. We acknowledge your comments regarding the manuscript's structure and the organization of information across different sections. To address this, we carefully revised the manuscript to ensure a more coherent and logical flow. We also worked on restructuring the discussion section to enhance clarity and improve its alignment with the study’s findings.

Introduction

2. The introduction looks very long and should be reorganized, with a maximum structure of 3 or 4 paragraphs. In some parts, authors seem to be throwing out ideas for discussion about the subject matter, but they are not argued and remain as free sentences. The number of paragraphs of less than 10 lines hinders the reader from jumping to ideas. Provide more information about MEF and its used in previous studies

R/ Thank you for your valuable feedback. In response to your comments, we have shortened and reorganized the introduction to improve clarity and focus. The revised introduction is now structured into fewer paragraphs, ensuring a smoother flow and better alignment with the manuscript's objectives. Additionally, we have clarified the role of middle ear fluid (MEF) analysis in AOM research and provided relevant information to address the reviewer's request (Pages 3-4; lines 52-103).

3. The initial sentence in paragraph 4 should be modified. Also, reference number 4 does not support the sentence; there are many different pathways related to the development of SPN AOM. SPN colonization is considered a prerequisite, but there is some controversial data in this regard.

R/ Thank you for recommendation. We have carefully reviewed the references and incorporated new references that better support the statement regarding the pathways involved in SPN AOM development and the role of SPN colonization as a prerequisite, acknowledging the existing controversy in the literature (Pages 3-4; lines 52-103).

4. Paragraph 5 does not include meningitis as a complication; relevant data about SPN AOM igniting invasive pneumococcal disease is available. this paragraph is weak; it lacks data on vaccination, vaccination coverage, and circulating serotypes. Colombian literature on these topics has been written by authors such as Severiche et al. and Serrano et al.

R/ After updating introduction and shorten its length, paragraph 2 mentions meningitis as a complication "Among its complications, otomastoiditis is the most prevalent, although severe conditions such as meningitis and encephalitis have also been documented (9). In paragraph 3, data on vaccination, vaccination coverage, and circulating serotypes is presented (Page 4; lines 70-83).

5. Paragraph 6 mentioned several studies, but the references do not match. You should revise the metanalysis in this regard. There is so much information in children rather than in adults. The section that refers to the SPN capsular switch needs more data and support.

R/ Thank you for your insight. Since introduction has been shortened, the order of paragraphs has changed. Meningitis as a complication is now mentioned in paragraph 2. Paragraph 3 contains relevant and precise information about SPN vaccination coverage. The suggested references have been added to the paragraphs (Page 4; lines 70-83).

6. Paragraph 7, please include the rates of effective vaccination in Colombia with the previous two vaccines. To provide background information to the reader about which vaccine provided “protection” while the study was being performed.

R/ The paragraph has been revised, and we have incorporated vaccination coverage rates to provide a clearer epidemiological context. The revised text now states:

"In 2011, PCV10 was incorporated into the national immunization program and became universally available in 2012, reaching 89% coverage (23,24). The introduction of PCV-10 led to an 84.7% national reduction in IPD due to vaccine serotypes in children under five years of age (25,26). By 2019, national vaccination coverage reached >90%, although significant variability was observed among departments; for instance, in Bolívar, S. pneumoniae vaccination historically lagged behind national rates, reaching 80–89% coverage in 2021." (Page 4; lines 77-83).

7. Paragraph 8: Please provide the numbers for the decrease in incidence.

R/ The paragraph has been revised to ensure accuracy regarding decrease in incidence of IPD in Colombia as follows:

“The introduction of PCV-10 led to an 84.7% national reduction in invasive pneumococcal disease (IPD) due to vaccine serotypes in children under five years of age" (Page 4; lines 78-80).

Methods

8. Please provide clear information about the type of study. Is this a monocentric study? (provide a line saying so )

R/ We appreciated your suggestion. The sentence has been modified, as follows:

“This prospective observational cohort single-center study included children aged 3 to 59 months diagnosed with AOM who consulted the Napoleon Franco Pareja Children's Hospital in Cartagena, Colombia” (Page 5; lines 105-106).

9. What kind of guidelines were followed to perform a study on children? Please provide some lines in the first paragraph of methods standing the Helsinki declaration, the informed consent process, and the approval of an ethical committee. Consider moving the ethical considerations section after the first paragraph as this is a study performed in children.

R/ Thanks, we have moved the ethical considerations section after the first paragraph of methods. Also, we have added this sentence

"All study procedures were implemented in compliance with the Helsinki Declaration" and additional supplementary information about consent informed form (Page 6; lines 110-121).

10. Tympanocentesis is an invasive procedure with several risks, I would like the authors to provide supplemental information with a copy of the informed consent.

R/ We understand your inquiry. However, Tympanocentesis was not routinely done in all cases, it was only performed in one patient who presented clinical complications and who also had positive Streptococcus pneumoniae. Also, we added informed consent form as supporting information (See S1 Text. Informed consent form ) (Page 6; line 116; Page 15 lines 270-272).

11. How did the authors avoid reporting a false SPN such as Streptococcus pseudonemoniae, which usually shows alpha hemolysis halo and sensitivity to optokine?

R/ Thank you very much for this excellent question. Although Streptococcus pseudopneumoniae, is a different species from Streptococcus pneumoniae, shows a similarity of almost 50% with pneumococcus. To avoid reporting false pneumococcus, the following was done:

Phenotypic tests were performed such as:

1. The optochin test: the strains that showed alpha-hemolysis were inoculated on sheep blood agar in a CO2 incubator (5-10%) and a 5 mg optochin disk was placed and incubated for 18-24 hours at a temperature of 37ºC. After this, the strains were reviewed and those that had an inhibition halo > 14 mm (sensitive to optochin) confirmed the presence of pneumococcus, since streptococcus pseudopneumoniae is resistant to optochin when its strains are exposed to a CO2 atmosphere of 5-10%. For this reason, we did not leave the strains incubating with optochin in a normal atmosphere because then streptococcus pseudopneumoniae is sensitive to optochin.

2. The

Attachment

Submitted filename: Response to Reviewers.pdf

pone.0326660.s003.pdf^{(198.1KB, pdf)}

PLoS One. doi: 10.1371/journal.pone.0326660.r003

Decision Letter 1

Luis Felipe Reyes

Dear Dr. Alvis Guzman,

Please submit your revised manuscript by May 23 2025 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org . When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

We look forward to receiving your revised manuscript.

Kind regards,

Luis Felipe Reyes, M.D., Ph.D., MSc.

Academic Editor

PLOS ONE

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

Reviewer #1: All comments have been addressed

Reviewer #2: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions??>

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously? -->?>

Reviewer #1: N/A

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available??>

The PLOS Data policy

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #1: Yes

Reviewer #2: Yes

**********

Reviewer #1: I want to thank the authors for their effort and dedication. They have responded to the suggestions made in the previous revision, and their manuscript is now a better version.

Despite the improvement of this manuscript, some suggestions persist, and I quote below:

1. In line 52, a reference is missing to support this sentence.

2. The study by Sierra Lopez and Zapata should also be included in the introduction to give specific context to the entity in question.

3. It is important to review the lines referring to the introduction of the vaccines; the flow of information varies from global to local contexts repeatedly and can confuse the reader. I suggest introducing the complete global context and ending with the local context. lines 76-77

4. Line 83 has no reference

5. I understand that for safe handling of sensitive data, the hospital information cannot be accessed; however, in the methodology, they mention that case definitions were made, and then, based on this, inclusion and exclusion criteria were applied. I have two doubts about this: 1. The definition of case 2 includes unspecific symptoms of systemic infection that, in the age of the selected population, encompasses a broad spectrum of entities. It is also unclear whether the definition should include all symptoms or just one. Thus, is why it would be important to show how many cases were defined as case definition 1 o r case definition 2 and then which ones met the inclusion criteria. to modify the figure 1. In case you do not have or can not show the suggested data, explain better the screening and recruitment method. Were all patients who met a case definition (1 or 2) assessed to evaluate inclusion and exclusion criteria, and then it was defined that they entered the study?

6. Regarding MEF sample collection, no references are cited to support the procedure used in this study. Is the sampling protocol proprietary? Was it adapted? I request the authors to provide further information in this regard.

7. Since the authors' results suggest existing differences in the groups' characteristics, it would be worthwhile to analyze the difference through the appropriate statistical tests and add the p-value of this result to Table 1. This would evidence the differences.

8. There appears to be a difference in median age between patients with PNS and those with other causes, which should be discussed further. Could this be related to the increase in transient SPN colonization of the nasopharynx in school children?

9. In the discussion, when referring to the vaccine recommendation, other types of vaccines, such as PCV10-SII (PNEUMOSIL) that protect against SPN serotypes 1, 5, 6A, 6B, 7F, 9V, 14, 19A, 19F, and 23F are not discussed. PCV-15 and PCV-20 are not mentioned either. Likewise, this recommendation does not make sense because the phenomenon of capsular replacement in other countries has already shown that once the vaccine is changed, the circulating serotypes begin to change in the following 5-10 years. Colombia started vaccination with PCV-13 3 years ago after many countries included PCV-15 in their programs. The discussion about the recommendation for the next vaccine should revolve around vaccines after PCV-13. Suggested references PMID (38336559, 39591182, 39153492)

10. Although one of their important findings is that serotype 19a was found in a higher proportion, they do not discuss how, in Colombia, this circulating serotype is also the major cause of IPD PMID (34641809,32964223).

11. There are paragraphs in the discussion that merely mention facts but do not contradict or support the researchers' findings and do not contribute to the scope referred to in the objective. Examples of these are found in lines 344-347, 357-367, and 386-389.

12. I kindly suggest refining the information in the discussion to make the reader understand in a more adequate way the importance of the findings and how this study is the basis for further research on pneumococcal diseases different from IPD, as well as how the impact of the vaccination that has been applied to the Colombian context is reflected in its results and could be modified with the introduction of other vaccines.

I consider the findings of this group of researchers very valuable. I believe this study could be the cornerstone for implementing a program of active surveillance and tracking of causes of acute otitis media. I hope my suggestions can be incorporated into an improved version of their wonderful work.

Reviewer #2: (No Response)

**********

what does this mean? ). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy

Reviewer #1: No

Reviewer #2: Yes: German Camacho Moreno

**********

PLoS One. 2025 Jul 28;20(7):e0326660. doi: 10.1371/journal.pone.0326660.r004

Author response to Decision Letter 2

23 May 2025

Luis Felipe Reyes, MD, MSc. PhD

Academic editor

PLOS ONE

Dear Dr. Reyes and reviewers,

We thank the reviewers for their thorough evaluation and constructive comments. In response, we have carefully revised the manuscript to address all points raised. Below, we detail each reviewer’s comment followed by our response and a summary of the changes made in the revised version of the manuscript.

Comment 1

Reviewer comment:

In line 52, a reference is missing to support this sentence.

Author response:

A reference has been added to the aforementioned line: “Gavrilovici C, Spoială EL, Miron IC, Stârcea IM, Haliţchi COI, Zetu IN, et al. Acute Otitis Media in Children—Challenges of Antibiotic Resistance in the Post-Vaccination Era. Microorganisms. 2022;10(8).”

Comment 2

Reviewer comment:

The study by Sierra Lopez and Zapata should also be included in the introduction to give specific context to the entity in question.

Author response:

We included the study by Sierra et al. in the introduction to provide specific local context regarding the etiology of otitis media in Colombia. The following sentence was added (Lines 64–66): “In Colombia, similar trends have been observed; a study conducted in Cali reported that the most commonly isolated bacteria in pediatric otitis media cases were H. influenzae (31%) and S. pneumoniae (30%) (14).”

Comment 3

Reviewer comment:

It is important to review the lines referring to the introduction of the vaccines; the flow of information varies from global to local contexts repeatedly and can confuse the reader. I suggest introducing the complete global context and ending with the local context. lines 76-77

Author response:

We have reorganized lines 73–87 to improve the clarity and flow of information about the introduction of pneumococcal vaccines. The section now begins with the global perspective and then moves on to the national context in Colombia.

Comment 4

Reviewer comment:

Line 83 has no reference.

Author response:

Reference 29 was added: Rodríguez WC, Mora-Salamanca AF, et al. Pediatric invasive pneumococcal disease in Bolívar, Colombia. Infez Med. 2024;32(4):506–17.

Comment 5

Reviewer comment:

I understand that for safe handling of sensitive data, the hospital information cannot be accessed; however, in the methodology, they mention that case definitions were made, and then, based on this, inclusion and exclusion criteria were applied. I have two doubts about this: 1. The definition of case 2 includes unspecific symptoms of systemic infection that, in the age of the selected population, encompasses a broad spectrum of entities. It is also unclear whether the definition should include all symptoms or just one. Thus, is why it would be important to show how many cases were defined as case definition 1 o r case definition 2 and then which ones met the inclusion criteria. to modify the figure 1. In case you do not have or can not show the suggested data, explain better the screening and recruitment method. Were all patients who met a case definition (1 or 2) assessed to evaluate inclusion and exclusion criteria, and then it was defined that they entered the study?

Author response:

We revised the methodology to explain the two-step screening and diagnostic process. General physicians screened suspected cases using broad criteria (either otoscopic or systemic). All children who met these criteria were referred to an ENT specialist who confirmed AOM diagnosis using AAP standards. Only confirmed cases were assessed for eligibility. Unfortunately, the number of cases that met definition 1 or 2 separately was not recorded systematically. Figure 1 was not modified, but the recruitment explanation was clarified in the methods section.

Comment 6

Reviewer comment:

Regarding MEF sample collection, no references are cited to support the procedure used in this study. Is the sampling protocol proprietary? Was it adapted? I request the authors to provide further information in this regard.:

Author response:

We have now cited published methods to support the sample collection protocol (references 34 and 35).

34 Fekete S, Juhász J, Makra N, Dunai ZA, Kristóf K, Ostorházi E, et al. Characterization of middle ear microbiome in otitis media with effusion in Hungarian children: Alloiococcus otitidis may potentially hamper the microbial diversity. Heliyon [Internet]. 15 de noviembre de 2024;10(21):e39380. Disponible en: https://www.sciencedirect.com/science/article/pii/S2405844024154114

35. Marchisio P, Esposito S, Picca M, Baggi E, Terranova L, Orenti A, et al. Prospective evaluation of the aetiology of acute otitis media with spontaneous tympanic membrane perforation. Clin Microbiol Infect [Internet]. 1 de julio de 2017 [citado 5 de mayo de 2025];23(7):486.e1-486.e6. Disponible en: https://doi.org/10.1016/j.cmi.2017.01.010

Comment 7

Reviewer comment:

Since the authors' results suggest existing differences in the groups' characteristics, it would be worthwhile to analyze the difference through the appropriate statistical tests and add the p-value of this result to Table 1. This would evidence the differences.

Author response:

Thank you for your valuable observation. We agree that it would have been relevant to apply inferential statistics to compare the groups with respect to their sociodemographic characteristics. However, due to the small number of patients with S. pneumoniae (n = 6), the sample lacks sufficient statistical power to support meaningful comparisons. Therefore, we chose to present the data descriptively to avoid overinterpretation of underpowered analyses. Consequently, we also modified redaction in Results, in terms of not suggesting “differences” among groups: Line 241: “Among patients with AOM caused by microorganisms other than S. pneumoniae, thirty-three (60%) were male, with a median age of 12 months (IQR = 7 - 24).”

Comment 8

Reviewer comment:

There appears to be a difference in median age between patients with PNS and those with other causes, which should be discussed further. Could this be related to the increase in transient SPN colonization of the nasopharynx in school children?

Author response:

While children with S. pneumoniae were older, we cannot confirm statistical significance due to small sample size. We did run a Mann Whitney Test comparing age between the two groups and there was not statistical difference, however, we recognize the lack of power to ensure this result is not spurious. Therefore, we consider it not appropriate to make inferences about these differences in age.

Comment 9

Reviewer comment:

In the discussion, when referring to the vaccine recommendation, other types of vaccines, such as PCV10-SII (PNEUMOSIL) that protect against SPN serotypes 1, 5, 6A, 6B, 7F, 9V, 14, 19A, 19F, and 23F are not discussed. PCV-15 and PCV-20 are not mentioned either. Likewise, this recommendation does not make sense because the phenomenon of capsular replacement in other countries has already shown that once the vaccine is changed, the circulating serotypes begin to change in the following 5-10 years. Colombia started vaccination with PCV-13 3 years ago after many countries included PCV-15 in their programs. The discussion about the recommendation for the next vaccine should revolve around vaccines after PCV-13. Suggested references PMID (38336559, 39591182, 39153492)

Author response:

We have restructured discussion in regard to vaccine recommendations. We need, however, to recognize that PCV-13 is the current officially implemented vaccine in Colombia. Therefore, we framed our interpretation within this context.

In regard to other vaccines, we added a paragraph stating:

“As vaccine coverage expands to more serotypes, the replacement effect by non-vaccine serotypes (41) or other microorganisms will continue, as will the antimicrobial pressure due to the indiscriminate use of antibiotics. Among the cases of non-pneumococcal AOM, it was found that 25.5% of the participants received the PCV-13 vaccination schedule. This observation could serve as a baseline for future follow-ups to assess the effect of replacement by other microorganisms and serotypes. Pneumococcal surveillance to non-invasive disease, including serotyping and resistance profiling, is critical for tracking the community-level circulation of multidrug-resistant strains. We acknowledge the development and licensure of newer pneumococcal conjugate vaccines (PCV10-SII, PCV-15 and PCV-20) which offer broader serotype coverage and are under evaluation or currently used in various immunization programs of other countries (49–51), but these vaccines were not yet licensed in Colombia at the time of this study.”

Comment 10

Reviewer comment:

Although one of their important findings is that serotype 19a was found in a higher proportion, they do not discuss how, in Colombia, this circulating serotype is also the major cause of IPD PMID (34641809,32964223).

Author response:

Serotype 19A has emerged as a predominant serotype also in IPD. Its multidrug resistant pattern could be associated also to worse clinical outcomes such as IPD.

We added a sentence to highlight this: “Evidence of a similar behavior in Colombia regarding isolates of S. pneumoniae causing IPD was found, wherein 19A and 6C are predominant serotypes.”

Comment 11

Reviewer comment:

There are paragraphs in the discussion that merely mention facts but do not contradict or support the researchers' findings and do not contribute to the scope referred to in the objective. Examples of these are found in lines 344-347, 357-367, and 386-389.

Author response:

Thanks for your detailed revision of Discussion and meaningful suggestions. We revised the discussion and removed or integrated the identified sections into more cohesive and relevant paragraphs.

Comment 12

Reviewer comment:

I kindly suggest refining the information in the discussion to make the reader understand in a more adequate way the importance of the findings and how this study is the basis for further research on pneumococcal diseases different from IPD, as well as how the impact of the vaccination that has been applied to the Colombian context is reflected in its results and could be modified with the introduction of other vaccines.

Author response:

We reformulated the discussion to highlight key contributions: comparison with national studies, impact of vaccination on serotype distribution, the emergence of serotype 19A, and clinical aspects such as seasonality. Paragraphs were condensed to improve focus and readability.

Sincerely,

Nelson Alvis Guzman. PhD

Corresponding author

Universidad de la Costa

nalvis@cuc.edu.co

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Luis Felipe Reyes

Evaluation of Streptococcus pneumoniae as a cause of acute otitis media in Colombia: a prospective study

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Data Availability Statement

[pone.0326660.ref001] 1.Gavrilovici C, Spoială E-L, Miron I-C, Stârcea IM, Haliţchi COI, Zetu IN, et al. Acute Otitis Media in Children-Challenges of Antibiotic Resistance in the Post-Vaccination Era. Microorganisms. 2022;10(8):1598. doi: 10.3390/microorganisms10081598 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0326660.ref002] 2.Leung DY, Sampson H, Geha R, Szefler SJ. Pediatric allergy: principles and practice E-Book. Elsevier Health Sciences. 2010. [Google Scholar]

[pone.0326660.ref003] 3.Coronell-Rodríguez W, Arteta-Acosta C, Alvis-Zakzuk N, Alvis-Guzmán N. Costs of acute otitis media in children in a city of the Colombian Caribbean coast. Biomédica [Internet]. 31 de marzo de 2019 [citado 17 de julio de 2023];39(1):75–87. https://www.revistabiomedica.org/index.php/biomedica/article/view/3784 [DOI] [PubMed] [Google Scholar]

[pone.0326660.ref004] 4.Coronell-Rodríguez W, Arteta-Acosta C, Osorio-Anaya S, Hoz FDL, Alvis-Guzman N. Incidence of Acute Otitis Media in the Vaccines Era Against Pneumococcus in a City of the Colombia Caribbean Coast: A Cohort Study. Open Forum Infectious Diseases. 2016;3(suppl_1). doi: 10.1093/ofid/ofw172.654 [DOI] [Google Scholar]

[pone.0326660.ref005] 5.Barajas Viracachá NC. Prevalencia de serotipos de Streptococcus pneumoniae y otros gérmenes causantes de otitis media aguda en niños de Latinoamérica. Revisión sistemática de la bibliografía. Arch Argent Pediatría. 2011;109(3):204–12. [DOI] [PubMed] [Google Scholar]

[pone.0326660.ref006] 6.Vergison A. Microbiology of otitis media: a moving target. Vaccine. 2008;26 Suppl 7:G5-10. doi: 10.1016/j.vaccine.2008.11.006 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0326660.ref007] 7.Pichichero ME. Immunologic dysfunction contributes to the otitis prone condition. J Infect. 2020;80(6):614–22. doi: 10.1016/j.jinf.2020.03.017 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0326660.ref008] 8.Gisselsson-Solén M, Henriksson G, Hermansson A, Melhus A. Risk factors for carriage of AOM pathogens during the first 3 years of life in children with early onset of acute otitis media. Acta Otolaryngol. 2014;134(7):684–90. doi: 10.3109/00016489.2014.890291 [DOI] [PubMed] [Google Scholar]

[pone.0326660.ref009] 9.Trujillo H, Callejas R, Mejía GI, Castrillón L. Bacteriology of middle ear fluid specimens obtained by tympanocentesis from 111 Colombian children with acute otitis media. Pediatr Infect Dis J. 1989;8(6):361–3. doi: 10.1097/00006454-198906000-00007 [DOI] [PubMed] [Google Scholar]

[pone.0326660.ref010] 10.Allemann A, Frey PM, Brugger SD, Hilty M. Pneumococcal carriage and serotype variation before and after introduction of pneumococcal conjugate vaccines in patients with acute otitis media in Switzerland. Vaccine. 2017;35(15):1946–53. doi: 10.1016/j.vaccine.2017.02.010 [DOI] [PubMed] [Google Scholar]

[pone.0326660.ref011] 11.Barenkamp SJ, Chonmaitree T, Hakansson AP, Heikkinen T, King S, Nokso-Koivisto J, et al. Panel 4: Report of the Microbiology Panel. Otolaryngol Head Neck Surg. 2017;156(4_suppl):S51–62. doi: 10.1177/0194599816639028 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0326660.ref012] 12.Schilder AGM, Chonmaitree T, Cripps AW, Rosenfeld RM, Casselbrant ML, Haggard MP, et al. Otitis media. Nat Rev Dis Primers. 2016;2(1):16063. doi: 10.1038/nrdp.2016.63 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0326660.ref013] 13.Mather MW, Drinnan M, Perry JD, Powell S, Wilson JA, Powell J. A systematic review and meta-analysis of antimicrobial resistance in paediatric acute otitis media. Int J Pediatr Otorhinolaryngol. 2019;123:102–9. doi: 10.1016/j.ijporl.2019.04.041 [DOI] [PubMed] [Google Scholar]

[pone.0326660.ref014] 14.Sierra A, Lopez P, Zapata MA, Vanegas B, Castrejon MM, Deantonio R, et al. Non-typeable Haemophilus influenzae and Streptococcus pneumoniae as primary causes of acute otitis media in colombian children: a prospective study. BMC Infect Dis. 2011;11:4. doi: 10.1186/1471-2334-11-4 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0326660.ref015] 15.Chacon-Cruz E, Lopatynsky EZ. Continuous Effectiveness of Pneumococcal 13-Valent Conjugate Vaccine on Pediatric Pneumococcal Otomastoiditis: Results of 15 Years of Active/Prospective Surveillance in a Mexican Hospital on the Mexico-US Border. Cureus. 2021;13(8):e17608. doi: 10.7759/cureus.17608 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0326660.ref016] 16.Ren Y, Sethi RKV, Stankovic KM. Acute Otitis Media and Associated Complications in United States Emergency Departments. Otol Neurotol Off Publ Am Otol Soc Am Neurotol Soc Eur Acad Otol Neurotol. 2018;39(8):1005–11. doi: 10.1097/MAO.0000000000001929 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0326660.ref017] 17.Lavin JM, Rusher T, Shah RK. Complications of Pediatric Otitis Media. Otolaryngol Head Neck Surg. 2016;154(2):366–70. doi: 10.1177/0194599815611860 [DOI] [PubMed] [Google Scholar]

[pone.0326660.ref018] 18.Kaur R, Fuji N, Pichichero ME. Dynamic changes in otopathogens colonizing the nasopharynx and causing acute otitis media in children after 13-valent (PCV13) pneumococcal conjugate vaccination during 2015-2019. Eur J Clin Microbiol Infect Dis. 2022;41(1):37–44. doi: 10.1007/s10096-021-04324-0 [DOI] [PubMed] [Google Scholar]

[pone.0326660.ref019] 19.Ordoñez J, Quitián D. PCN57 Cost-Effectiveness of Venetoclax in Combination with Obinutuzumab in First LINE Chronic Lymphocytic Leukemia in Colombia. Value in Health. 2021;24:S29. doi: 10.1016/j.jval.2021.04.149 [DOI] [Google Scholar]

[pone.0326660.ref020] 20.Fortanier AC, Venekamp RP, Boonacker CW, Hak E, Schilder AG, Sanders EA, et al. Pneumococcal conjugate vaccines for preventing acute otitis media in children. Cochrane Database Syst Rev. 2019;5(5):CD001480. doi: 10.1002/14651858.CD001480.pub5 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0326660.ref021] 21.de Sévaux JL, Venekamp RP, Lutje V, Hak E, Schilder AG, Sanders EA, et al. Pneumococcal conjugate vaccines for preventing acute otitis media in children. Cochrane Database Syst Rev. 2020;11(11):CD001480. doi: 10.1002/14651858.CD001480.pub6 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0326660.ref022] 22.Whitney CG, Farley MM, Hadler J, Harrison LH, Bennett NM, Lynfield R, et al. Decline in invasive pneumococcal disease after the introduction of protein-polysaccharide conjugate vaccine. N Engl J Med. 2003;348(18):1737–46. doi: 10.1056/NEJMoa022823 [DOI] [PubMed] [Google Scholar]

[pone.0326660.ref023] 23.Martin JM, Hoberman A, Paradise JL, Barbadora KA, Shaikh N, Bhatnagar S, et al. Emergence of Streptococcus pneumoniae serogroups 15 and 35 in nasopharyngeal cultures from young children with acute otitis media. Pediatr Infect Dis J. 2014;33(11):e286-290. [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0326660.ref024] 24.de Oliveira LH, Camacho LAB, Coutinho ESF, Martinez-Silveira MS, Carvalho AF, Ruiz-Matus C, et al. Impact and Effectiveness of 10 and 13-Valent Pneumococcal Conjugate Vaccines on Hospitalization and Mortality in Children Aged Less than 5 Years in Latin American Countries: A Systematic Review. PLoS One. 2016;11(12):e0166736. doi: 10.1371/journal.pone.0166736 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0326660.ref025] 25.Torres Martinez C, Camacho Moreno G, Patiño Niño J, Coronell Rodríguez W, Leal AL, Gámez G. Pneumococcal diseases in Colombia: epidemiological analysis before and during the universal children immunization against Streptococcus pneumoniae in the light of a vaccine change in 2022. Infect Rev Asoc Colomb Infectol. 2024;28(1):8. https://dialnet.unirioja.es/servlet/articulo?codigo=9365352 [Google Scholar]

[pone.0326660.ref026] 26.Camacho-Moreno G, Leal AL, Patiño-Niño J, Vasquez-Hoyos P, Gutiérrez I, Beltrán S, et al. Serotype distribution, clinical characteristics, and antimicrobial resistance of pediatric invasive pneumococcal disease in Colombia during PCV10 mass vaccination (2017-2022). Front Med. 2024;11:1380125. [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0326660.ref027] 27.Agudelo CI, Castañeda-Orjuela C, Brandileone MCDC, Echániz-Aviles G, Almeida SCG, Carnalla-Barajas MN, et al. The direct effect of pneumococcal conjugate vaccines on invasive pneumococcal disease in children in the Latin American and Caribbean region (SIREVA 2006–17): a multicentre, retrospective observational study. Lancet Infect Dis. 2021;21(3):405–17. [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0326660.ref028] 28.Severiche-Bueno DF, Severiche-Bueno DF, Bastidas A, Caceres EL, Silva E, Lozada J, et al. Burden of invasive pneumococcal disease (IPD) over a 10-year period in Bogotá, Colombia. Int J Infect Dis. 2021;105:32–9. doi: 10.1016/j.ijid.2021.02.031 [DOI] [PubMed] [Google Scholar]

[pone.0326660.ref029] 29.Rodríguez WC, Mora-Salamanca AF, Santacruz-Arias J, Alvarado-Gonzalez JC, Saavedra L, Pinzón-Redondo H. Pediatric invasive pneumococcal disease in Bolívar, Colombia: a descriptive cross-sectional study. Infez Med. 2024;32(4):506–17. [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0326660.ref030] 30.Programa Ampliado de Inmunizaciones PAI. Lineamientos técnicos y operativos para la transición de la vacuna polisacárida contra el neumococo de PCV10 a PCV13 en Colombia. 2022. https://www.minsalud.gov.co/sites/rid/Lists/BibliotecaDigital/RIDE/VS/PP/ET/lineamiento-tecnico-operativo-transicion-vacuna-polisacarda-contra-neumococo-pcv10-pcv13-colombia-2022.pdf [Google Scholar]

[pone.0326660.ref031] 31.Carrasquilla G, Porras-Ramírez A, Martinez S, DeAntonio R, Devadiga R, Talarico C, et al. Trends in all-cause pneumonia and otitis media in children aged <2 years following pneumococcal conjugate vaccine introduction in Colombia. Hum Vaccin Immunother. 2021;17(4):1173–80. doi: 10.1080/21645515.2020.1805990 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0326660.ref032] 32.Coronell-Rodríguez W, Arteta-Acosta C, Osorio-Anaya S, Mejia-Bermudez S, Hoz FDL, Alvis-Guzman N. Effectiveness of Pneumococcal Conjugate Vaccine PCV10 in a City of the Colombian Caribbean: Case-Control Study Nested in a Cohort. Open Forum Infectious Diseases. 2016;3(suppl_1). doi: 10.1093/ofid/ofw172.639 [DOI] [Google Scholar]

[pone.0326660.ref033] 33.Ministerio de Salud y Protección Social. Resolución 8430 de 1993: por la cual se establecen las normas científicas, técnicas y administrativas para la investigación en salud. 1993. https://www.minsalud.gov.co/sites/rid/Lists/BibliotecaDigital/RIDE/DE/DIJ/RESOLUCION-8430-DE-1993.PDF [Google Scholar]

[pone.0326660.ref034] 34.Ministerio de Salud y Protección Social. Afiliación en salud. 2023. https://www.minsalud.gov.co/proteccionsocial/Paginas/afiliacion-en-salud.aspx [Google Scholar]

[pone.0326660.ref035] 35.Lieberthal AS, Carroll AE, Chonmaitree T, Ganiats TG, Hoberman A, Jackson MA, et al. The diagnosis and management of acute otitis media. Pediatrics. 2013;131(3):e964-99. doi: 10.1542/peds.2012-3488 [DOI] [PubMed] [Google Scholar]

[pone.0326660.ref036] 36.Fekete S, Juhász J, Makra N, Dunai ZA, Kristóf K, Ostorházi E, et al. Characterization of middle ear microbiome in otitis media with effusion in Hungarian children: Alloiococcus otitidis may potentially hamper the microbial diversity. Heliyon. 2024;10(21):e39380. doi: 10.1016/j.heliyon.2024.e39380 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0326660.ref037] 37.Marchisio P, Esposito S, Picca M, Baggi E, Terranova L, Orenti A, et al. Prospective evaluation of the aetiology of acute otitis media with spontaneous tympanic membrane perforation. Clin Microbiol Infect. 2017;23(7):486.e1-486.e6. doi: 10.1016/j.cmi.2017.01.010 [DOI] [PubMed] [Google Scholar]

[pone.0326660.ref038] 38.Departamento Administrativo Nacional de Estadística (DANE). Proyecciones de población [Internet]. Disponible en: https://www.dane.gov.co/index.php/estadisticas-por-tema/demografia-y-poblacion/proyecciones-de-poblacion [Google Scholar]

[pone.0326660.ref039] 39.Moreno J, Duarte C, Cassiolato AP, Chacón GC, Alarcon P, Sánchez J, et al. Molecular characterization of Latin American invasive Streptococcus pneumoniae serotype 19A isolates. Vaccine. 2020;38(19):3524–30. doi: 10.1016/j.vaccine.2020.03.030 [DOI] [PubMed] [Google Scholar]

[pone.0326660.ref040] 40.Zissis NP, Syriopoulou V, Kafetzis D, Daikos GL, Tsilimingaki A, Galanakis E, et al. Serotype distribution and antimicrobial susceptibility of Streptococcus pneumoniae causing invasive infections and acute otitis media in children. Eur J Pediatr. 2004;163(7):364–8. doi: 10.1007/s00431-004-1447-4 [DOI] [PubMed] [Google Scholar]

[pone.0326660.ref041] 41.Instituto Nacional de Salud. Vigilancia por laboratorio de Streptococcus pneumoniae en Colombia, 2016-2021. Instituto Nacional de Salud. 2021. https://www.ins.gov.co/BibliotecaDigital/vigilancia-por-laboratorio-de-streptococcus-pneumoniae-en-colombia-2016-2021.pdf [Google Scholar]

[pone.0326660.ref042] 42.Hausdorff WP, Siber G, Paradiso PR. Geographical differences in invasive pneumococcal disease rates and serotype frequency in young children. Lancet. 2001;357(9260):950–2. doi: 10.1016/S0140-6736(00)04222-7 [DOI] [PubMed] [Google Scholar]

[pone.0326660.ref043] 43.Løchen A, Croucher NJ, Anderson RM. Divergent serotype replacement trends and increasing diversity in pneumococcal disease in high income settings reduce the benefit of expanding vaccine valency. Sci Rep. 2020;10(1):18977. [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0326660.ref044] 44.Gatti B, Ramírez Gronda G, Etchevarría M, Vescina C, Varea A, González Ayala SE. Aislamiento de distintos serotipos de Haemophilus influenzae en muestras profundas de pacientes pediátricos. Rev Argent Microbiol. 2004;36:20–3. [PubMed] [Google Scholar]

[pone.0326660.ref045] 45.Fuentes Gort K, Tamargo Martínez I, Toraño Peraza G. Susceptibilidad antimicrobiana en cepas de Haemophilus influenzae no tipables aisladas en niños sanos. Rev Cuba Med Trop. 2004;56(2):139–4. [PubMed] [Google Scholar]

[pone.0326660.ref046] 46.Falup-Pecurariu O, Leibovitz E, Mercas A, Bleotu L, Zavarache C, Porat N, et al. Pneumococcal acute otitis media in infants and children in central Romania, 2009-2011: microbiological characteristics and potential coverage by pneumococcal conjugate vaccines. Int J Infect Dis. 2013;17(9):e702-6. doi: 10.1016/j.ijid.2013.02.002 [DOI] [PubMed] [Google Scholar]

[pone.0326660.ref047] 47.Chonmaitree T. Viral and bacterial interaction in acute otitis media. Pediatr Infect Dis J. 2000;19(5 Suppl):S24-30. doi: 10.1097/00006454-200005001-00005 [DOI] [PubMed] [Google Scholar]

[pone.0326660.ref048] 48.Ruohola A, Pettigrew MM, Lindholm L, Jalava J, Räisänen KS, Vainionpää R, et al. Bacterial and viral interactions within the nasopharynx contribute to the risk of acute otitis media. J Infect. 2013;66(3):247–54. doi: 10.1016/j.jinf.2012.12.002 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0326660.ref049] 49.Sistema Integrado de Información de la Protección Social. https://www.sispro.gov.co/Pages/Home.aspx. 2023 October 1. [Google Scholar]

[pone.0326660.ref050] 50.Paul CR, Moreno MA. Acute Otitis Media. JAMA Pediatr. 2020;174(3):308. doi: 10.1001/jamapediatrics.2019.5664 [DOI] [PubMed] [Google Scholar]

[pone.0326660.ref051] 51.Serrano-Mayorga CC, Ibáñez-Prada ED, Restrepo-Martínez JM, Garcia-Gallo E, Duque S, Severiche-Bueno DF. The potential impact of PCV-13, PCV-15 and PCV-20 vaccines in Colombia. Vaccine. 2024;42(7):1435–9. [DOI] [PubMed] [Google Scholar]

[pone.0326660.ref052] 52.Ilic A, Tort MJ, Cane A, Farkouh RA, Rozenbaum MH. The Health and Economic Effects of PCV15 and PCV20 During the First Year of Life in the US. Vaccines (Basel). 2024;12(11):1279. doi: 10.3390/vaccines12111279 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0326660.ref053] 53.Choi YH, Bertran M, Litt DJ, Ladhani SN, Miller E. Potential impact of replacing the 13-valent pneumococcal conjugate vaccine with 15-valent or 20-valent pneumococcal conjugate vaccine in the 1 + 1 infant schedule in England: a modelling study. Lancet Public Health. 2024;9(9):e654–63. doi: 10.1016/S2468-2667(24)00161-0 [DOI] [PubMed] [Google Scholar]

PERMALINK

Evaluation of Streptococcus pneumoniae as a cause of acute otitis media in Colombia: A prospective study

Wilfrido Coronell-Rodriguez

Rosanna Camerano

Juan Carlos Alvarado-Gonzalez

Alejandra Puerto

Josefina Zakzuk

Nelson R Alvis-Zakzuk

Lina Moyano-Tamara

Sebastian Medina

Claudia Beltran

Maria Betancur

Monica Rojas

Luis Enrique Farias

Hernando Pinzon-Redondo

Perla Villamor

Steven Osorio

Nelson Alvis-Guzmán

Roles

Abstract

Objective

Methods

Results

Conclusion

Introduction

Materials and methods

Fig 1. Overview of the study’s workflow.

Ethical considerations

Population and selection criteria

Sample collection

Laboratory analysis

Follow-up

Data analysis

Results

Fig 2. Inclusion trends of AOM patients.

Table 1. Sociodemographic characteristics of patients.

Table 2. Clinical characteristics of patients.

Fig 3. Microorganisms isolated from MEF cultures (n = 61 isolations).

Fig 4. Resistance pattern of S. pneumoniae serotypes to antimicrobial groups (n = 6 isolations).

Table 3. Outcome of cases with S. pneumoniae isolation.

Discussion

Conclusions

Supporting information

Acknowledgments

Data Availability

Funding Statement

References

Decision Letter 0

Luis Felipe Reyes

Roles

Author response to Decision Letter 1

Decision Letter 1

Luis Felipe Reyes

Roles

Author response to Decision Letter 2

Decision Letter 2

Luis Felipe Reyes

Roles

Acceptance letter

Luis Felipe Reyes

Roles

Associated Data

Supplementary Materials

Data Availability Statement

ACTIONS

PERMALINK

RESOURCES

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