Surgical Site Infections: Prospective Study in a Medical College Teaching Hospital at Port Blair, India

Abstract

Objectives:

Surgical site infections (SSIs) continue to be a prevalent and pervasive issue, contributing to healthcare expenditures, extended hospital stays, and significantly increased morbidity and death. The purpose of the current study was to evaluate the risk factors and prevalence of SSIs amongst patients undergoing various surgical procedures at a tertiary care facility in Port Blair, India.

Materials and Methods:

This prospective study was conducted at a tertiary medical college hospital setting in Port Blair, India, within the Department of Microbiology. The study was conducted from January 2018 to June 2018.

Results:

During the study period, 776 individuals underwent various surgeries, including both elective and emergency procedures. The total prevalence of the SSI rate during the study period was 12.88% (n = 776) based on the documentation of approximately 100 SSIs. Amongst these, 44% were associated with obstetrics and gynaecology surgery. The category of post-lower segment caesarean section (LSCS) stitch line had the greatest prevalence rate of SSIs (34 patients out of 175 developed infections; LSCS approximately 19.42% of these patients developed SSIs).

Conclusions:

In Indian adult patients undergoing any form of surgical procedure, the SSI prevalence was 12.88%. SSIs occurred more frequently after obstetrics and gynaecology operations. Following any type of surgery, patients who are women, younger, had emergency surgery, have diabetes, and require a lengthy hospital stay are more likely to experience SSIs. The most commonly encountered pathogens were Staphylococcus aureus and coagulase negative Staphylococcus.

Introduction

Surgical site infections (SSIs) represent a common post-operative complication with significant risks of morbidity and mortality. They occur when bacteria enter the surgical wound and begin to increase. SSIs can be deep, affecting tissues beneath the skin, organs, or implanted material, or superficial, affecting only the skin.[1] SSIs are defined as infections that damage the incision or deep tissue at the operation site and manifest within 30 days following surgery or a year if an implant is left in place following the treatment.[2] The National Nosocomial Infection Surveillance Program (NNIS) categorises SSIs into three categories: superficial, deep, and organ/space infections.[3] The World Health Organization states that SSIs annually endanger the lives of millions of patients and contribute to the development of antibiotic resistance.[2] When local and systemic host defenses are compromised, organisms can penetrate tissues, leading to wound infection, which can cause cellulitis, lymphangitis, abscesses, and bacteraemia. SSIs are infections that develop in surgical sites.[1]

The patient’s natural flora, organisms from the hospital environment to which the patient is exposed during medical operations, certain underlying disorders, trauma, or burns that could disrupt the mucosal or skin surface are some of the sources of SSIs.[4] After respiratory and urinary tract infections, SSIs are the third most common nosocomial infection, according to numerous studies.[2,4] According to recent studies, the global SSI rate varies between 19.4% and 36.5%, whereas in India, it varies between 3% and 12%.[5,6,7] Length of hospital stay, obesity, diabetes mellitus, smoking, and other factors are known to contribute to SSIs. The development of a post-operative wound infection is dependent on the intricate interaction of numerous factors. While most post-operative wounds have an endogenous source of infection, exogenous infections are primarily acquired from the nose or skin flora of the operating team and spread through the surgeon’s hands or improper sterilisation of the operating theater, encompassing pre-operative, intraoperative, and post-operative care.[8] Notable factors affecting the frequency of recurrent infection include surgical techniques, skin preparation, timing, wound closure methods, and the use of antibiotic prophylaxis following specific procedures. Furthermore, a plethora of additional factors have been shown to influence the risk of infection, and medical practitioners should consider these factors before, during, and after surgery.[9] The data from rural India regarding SSI rates, prevention and protocols are sparse.

A comprehensive understanding of the incidence, risk factors, and outcomes associated with SSIs is crucial for optimising patient care and reducing healthcare-associated complications. This prospective study aims to investigate the occurrence of SSIs in a medical college teaching hospital located in Port Blair. By prospectively analysing various surgical interventions, this study aims to provide valuable insights into the specific dynamics of SSIs in this healthcare setting.

Materials and Methods

Study design

This prospective study was conducted at a tertiary medical college, Port Blair, India, specifically in the Department of Microbiology and Obstetrics and Gynaecology. The study was conducted from Jan 2018 to June 2018.

Inclusion criteria

The inclusion criteria are as follows:

1. Any surgery

2. Patients not having previous infections at surgical sites.

Exclusion criteria

The exclusion criteria are as follows:

1. Refusal to participate in the study.

2. Patients who were already receiving antibiotics for >1 week.

3. Patients below 15 years of age.

Details were recorded, including the type of surgery by wound class, type and duration of operation, antimicrobial prophylaxis if given, drain used, pre-operative stay, and total hospital stay. Each patient’s data were assessed from the time of admission until discharge from the hospital and also during follow-up visits, which extended up to 30–90 days depending on the case.

Diagnostic criteria

This study was conducted on the criteria based on the Centers for Disease Control and Prevention and the National Healthcare Safety Network, USA), as published in 2017.[10]

The surgical wound dressings were removed 48 h after the procedure. Any local inflammatory changes, such as edema redness, warmth, or discharge from the wound site, were considered as evidence of a wound infection. Before dressing the wounds, samples were collected to check if any discharge was present. Suspected wound infections were cleaned with sterile normal saline and 70% alcohol, and a sterile swab was used to collect the material. Within 2 h, the laboratory received two swabs taken from the depth of the wound, and/or the aspirates were collected in a sterile disposable syringe. The colour, consistency, and odour of the materials were noted. The patients were monitored for inflammatory symptoms with the assistance of their surgeons within 48 h. In addition, these patients received a 30-day mobile phone follow-up regarding the occurrence of SSIs.

Every wound swab and/or aspirate was directly smeared onto a glass slide and allowed to air dry. After heat-fixing, Gram staining was performed. Microorganisms and pus cells were observed when using the oil immersion (100×) objective. The materials were cultivated using conventional microbiological methods on 5% sheep blood agar and MacConkey agar plates. Plates were read after an aerobic 24-h incubation period at 37°C.

Ethical clearance

This study was carried out after obtaining ethical approval from the Institutional Research Board and Institutional Ethics Committee. Informed and written consent was obtained from every study subject.

Statistical analysis

Statistical Package for the Social Sciences (SPSS; IBM SPSS Statistics for Windows, Version 21.0, IBM Corp., Armonk, NY, USA) was used to analyse the data. The collected data were categorised and presented as a table showing frequency and percentage. A P value of less than 0.05 was considered statistically significant.

Results

During the study period, a total of 776 individuals underwent various surgeries, including both elective and emergency procedures. The total prevalence of the SSI rate during the study period was 12.88% (n = 776) based on the documentation of approximately 100 SSIs.

Table 1 displays the proportion of cases with SSIs based on the kind of operation. Of all SSIs, 44% occurred in obstetrics and gynaecology surgery. The category of post-lower segment caesarean section (LSCS) stitch line had the highest SSI prevalence rate (34 patients out of 175 patients developing infections, accounting for approximately 19.42% of these cases).

Table 1.

Proportion of cases with SSIs based on the kind of operation

Site of surgery	Types of surgeries	No. of surgeries	SSI, n (%)
Obstetrics and gynaecology	LSCS	175	34 (19.42%)
	Hysterectomy	55	5 (9.09%)
	episiotomy	105	5(4.76%)
General surgical procedures	Appendicectomies	72	8 (11.11%)
	Exploratory laparotomies	55	10(18.18%)
	Hernia repairs	47	6 (12.76%)
	Breast surgery	30	3 (10%)
	Hydrocele surgery	68	5 (7.35%)
Orthopaedic surgery	Open reduction and internal fixation	168	24(14.28%)
Total		776	100

The percentage of different organisms recovered from the various surgical sites is shown in Table 2. In obstetrics and gynaecology procedures, a large proportion of all the organisms (ranging from 9% to 56%) were isolated. The most commonly identified organisms from obstetrics and gynaecology procedures were Staphylococcus aureus, coagulase negative Staphylococcus, and Escherichia coli. Both Acinetobacter baumannii and Pseudomonas aeruginosa were recovered from different surgical sites.

Table 2.

The percentage of different organisms recovered from the various surgical sites

Organisms	General surgery (%)	Orthopaedics (%)	Obstetrics and gynaecology (%)
Staphylococcus aureus	21.8	33.33	56.81
Coagulase negative staphylococcus (CONS)	9.35	16.66	18.18
Escherichia coli	9.37	12.5	18.18
Klebsiella species (19)	12.5	16.66	2.27
Pseudomonas aeruginosa	6.25	0.83	4.54
Acinetobacter baumannii (9)	6.25	12.5	9.09

According to the SSI, Table 3 shows the study population’s risk variables and the relationship between the study participants’ risk variables and SSI infection. Approximately 31% of research participants aged between 26 and 35 years had a diagnosis of SSI (this proportion of patients was higher than that of patients in other age groups), with people in the 15–25 years age range being the second most prevalent age group at 29%.

Table 3.

Shown the study population’s risk variables and the relationship between the study participants’ risk variables and SSI infection

S. no	Risk factors		Frequency of SSI	P value
1	Age group (years)	15–25	29	<0.05
		26–35	31
		36–45	12
		46–55	17
		>55	11
2	Gender	Male	32	<0.05
		Female	68
3	Type of surgery	Emergency	89	<0.05
		Elective	11
4	Extend of wound	Superficial	90	<0.05
		Deep	10
		Organ	0
		Yes	61
6	Diabetes mellitus			<0.05
7	Smoking	Yes	35	0.562
		No	65
8	Alcoholism	Yes	37	0.764
		No	67
9	Hospital stay (days)	1–7	35	<0.05
		>7	65

In this study, 68% of SSI cases were diagnosed in women, and 89% of SSIs were detected during emergency procedures. There are three different types of SSIs: deep, superficial, and organ. Of the participants, 90% had superficial SSI, while the remaining 10% had deep ones.

Approximately 61% of participants with SSI had diabetes mellitus. Approximately 37% and 35%, respectively, of people with a history of alcoholism and smoking also had SSI. Similarly, 65% of patients who stayed longer than 7 days had an SSI diagnosis.

As shown in Table 3, the lower age group of 26-35 has a higher risk of developing SSI than other age groups. It has been observed that men are more likely than women to acquire SSI (P < 0.05). In addition, it has been observed that patients who underwent emergency surgery had a higher chance of having SSI than those who had elective surgery (P < 0.05). According to the observation, patients with diabetes had a greater chance of developing SSI than those without the disease (P < 0). There was no correlation between smoking habit and SSI (P = 0.56). Alcohol use habits did not significantly correlate with SSI in any of the patients (P = 0.76). The length of the hospital stay indicates that patients hospitalised for more than 7 days were more likely to get SSIs than those hospitalised for 7 days or less.

Discussion

In our study involving 776 patients undergoing various operations, obstetrics and gynaecology surgeries, including procedures such as LSCS, hysterectomy, and episiotomy, were performed in 335 patients, constituting a significant portion. General surgical procedures, such as appendicectomies and exploratory laparotomies, were conducted in 272 patients, while 168 patients underwent orthopedic treatments such as open reduction and internal fixation (ORIF). The elevated prevalence of SSIs, particularly in obstetrics and gynaecology surgeries, emphasises the necessity for targeted preventive measures in these procedures. Contrary to our findings, a study by Maksimović et al.[11] suggested a higher association between orthopedic operations and SSIs, indicating the need for further investigation in this context.

A total of 155 patients were suspected of post-operative wound infections based on local signs and symptoms, leading to a detailed assessment. Amongst them, 100 cases exhibited positive culture results, classifying them as SSI cases in our hospital and resulting in an overall prevalence rate of 12.88%.

However, the overall prevalence rate of SSIs was only 2.5% in the study conducted by Kumar and Rai[7] and Al-Mulhim et al.[12] According to research by Golia et al.[13] and Iqbal et al.,[14] the present status of SSIs found at their hospital is in line with their findings, which were 4.3%, 5.4%, and 7.3%, respectively. Setty et al.,[15] on the other hand, reported it as 21.66% and 22.2%.

In this study, the incidence of SSIs was statistically significantly higher in women than in men. In contrast to our study, men were more likely to experience these events (65.6%), according to a 2005 study by Hernandez et al.[16] conducted in a Peruvian hospital. In contrast, a study by Shanmugam et al.[17] found that the prevalence was about equal in males (48%) and females (52%). In the current study, the distribution of SSIs amongst study participants aged 25 years and older was almost equally distributed. The higher SSI occurrence in the 26–35 years age group and during emergency surgeries underscores the importance of age-specific and procedural considerations in infection control strategies. This may be related to the type of injury they sustained. However, individuals with diabetes mellitus and/or other co-morbid disorders, which lower physiological defense mechanisms and impair immunological function, often experience an increased incidence of SSIs with age. Numerous studies have corroborated it, including Owens and Stoessel[18] and Bharatnur and Agarwal[19] and it was reported that people between the ages of 36 and 50 years had a higher incidence of SSIs (1.3 times higher risk) than those in the 10- to 35-year range. Similarly, Mundhada and Tenpe[20] reported a significant infection rate in the latter age groups.

It was observed that the chances of developing SSIs amongst patients who underwent emergency surgeries were statistically significant (P < 0.05). The increased rate of SSIs in emergency surgeries may be due to a limited time span without proper patient preparation and surgical readiness, as well as contaminated wounds, such as those in cases of road traffic accidents. Most of the past studies agreed with this finding, and past studies on SSIs have cited the same. Tabiri et al.[21] noted that SSIs were more common in emergency cases (23.8%) compared to elective ones (7.4%). Dessie et al.[22] reported SSIs in 38.3% of elective cases and 61.7% of emergency cases. The number of superficial and deep SSIs in the current study was 90% and 10%, respectively. A higher superficial SSI was discovered. According to Kumar and Rai,[7] deep incisional SSI (169 cases, 44%) was less common than superficial incisional SSI (215 cases, 55.9%). van Walraven and Musselman[23] also showed that most of their patients (n = 8188, 57.5% of all SSIs) had a superficial component. However, these results contradict the findings of the Dessie et al. who reported that 42.1% of cases had superficial SSI and 57.9% of cases had deep SSI (112 cases).[22]

In our analysis, there was a statistically significant difference, with 61% more diabetic patients with SSI compared to non-diabetic. The current study’s finding that SSIs occur more amongst people with diabetics is consistent with studies by Lilienfeld et al.[24] and Talbot,[25] which reported 50% SSIs amongst people with diabetics.

In summary, our study underscores the significance of various factors such as the type of surgery, gender, age, emergency status, and underlying medical conditions, particularly diabetes, when assessing the risk and prevalence of SSIs. These findings emphasise the necessity for customised preventive strategies and further research to enhance our understanding of factors influencing SSIs in diverse surgical populations.

Conclusions

In Indian adult patients undergoing any form of surgery, the SSI prevalence was 12.88%. SSIs were more common after obstetrics and gynaecology operations. Following any type of surgery, women, younger patients, those who underwent emergency procedures, individuals with diabetes, and those requiring a lengthy hospital stay are more susceptible to experiencing SSIs. S. aureus was the most often encountered SSI, followed by Coagulase negative Staphylococcus.

Limitations of the study

The limitations of the study are as follows:

• This investigation is limited to aerobic bacterial pathogens and is conducted at a single centre.

• Patients below 15 years of age were excluded from this investigation.

• This study did not consider some circumstances, such as pre-operative preparation and subsequent procedures.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.