Incidence of Post-cesarean wound infections, bacterial profiles, resistant patterns, and associated costs among women delivering at public hospitals in Eastern Ethiopia: multi center study

Abstract

Background

Surgical site infection following cesarean section remains a serious public health issue worldwide, particularly in low and middle income countries. The global incidence of post-CS SSI recorded 5.63%.

Objective

To determine the incidence of post-cesarean wound infections, bacterial profiles, resistant patterns, and associated costs among women delivering at public hospitals in Eastern Ethiopia.

Methods

A hospital-based prospective study conducted at Hiwot Fana Specialized University Hospital, Dil Chora Referral Hospital, Dechatu Health center and Sabian General Hospital from January 01 to March 2025. Out of 427 mothers who underwent cesarean section were included. Socio-demographic data was gathered by personal interviews using a pre-tested questionnaire. Pus samples were collected using sterile cotton swab and inoculated in appropriate culture media. The Kirby-Bauer disk diffusion technique was employed to determine the antimicrobial resistance patterns of bacterial isolates. SPSS version 26 used to enter and analyze the data.

Results

From a total of 427 CS delivered mothers, 56 (13.1%) developed Post-CS SSI. Out of 56 isolates, 31 (55.3%) isolates were gram-positive organism and 25 (44.4%) isolates were gram-negative organisms. The predominant bacteria isolates were S. aureus (48.21%), K. pneumonia (17.8%), and E.coli (14.2%). The majority of isolates were resistant to tetracycline (83.3%), trimethoprim-sulfamethoxazole (88.8%), and amoxicillin-clavulanic acid (46.5%). Previous CS (p = 0.001), type of CS (p = 0.007), obesity (p < 0.001), hospital stay (p < 0.001), post-operative hemoglobin level (p = 0.015), residence (p = 0.006), and premature rupture of membrane (p < 0.001), showed statistically significant association with post-cesarean surgical site infection. The median(IQR) cost for laboratory, treatment, and hospital admission with and without post-cesarean surgical site infection were 894(126), 6161.50(551), and 3073(357) :540(219), 3334(1757), and 1600 (579) respectively.

Conclusion

The incidence of post cesarean surgical site infection was 13.1% and extra costs incurred on patients and health facilities. Implementation of a regular infection control policy along with microbiological work could reduce the incidence of post-CS SSI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-026-13199-5.

Background

Surgical site infection following cesarean section remains a serious public health issue worldwide, particularly in low and middle income countries. The global incidence of post-CS SSI recorded 5.63% [1]. In Africa, the estimated pooled prevalence is 11%, with substantial variation across the region, ranging from 5.03% in Tunisia to 34.1% in Tanzania [2]. The pooled prevalence of surgical site infection following cesarean section in Ethiopia was 11.13% which is higher than the global incidence [3]. Post–cesarean section surgical site infections contribute to maternal mortality and adversely affect neonatal health, interfere with breastfeeding, prolong hospital stay, and reduce mother–child interaction [4].

Cesarean section is the most common surgical procedure that is applied to deliver the fetus through an incision in the mother’s abdomen [5]. Based on the WHO report in 2021, cesarean section has increased worldwide and recorded more than 1 in 5 (21%) of all childbirths. Due to this, a continuous rise of infection is expected [6].

According to the Centers for Disease Control and Prevention (CDC) criteria, Post cesarean section surgical site infection is an infection that takes place at the surgery site and occurs within 30 days following cesarean section. It is a serious public health issue which causes maternal morbidity and mortality, prolonged hospital stays, readmission, re-operation and high excess hospital costs [7]. Predisposing risk factors are classified into two types: intrinsic and extrinsic. Intrinsic risk factors include age, body mass index (BMI), premature rupture of membranes, and host immune status. Extrinsic risk factors include previous cesarean section, antibiotic prophylaxis, type of cesarean section (elective or emergency), prolonged hospital stay, anemia, hypertension, and diabetes mellitus, all of which increase the risk of Post-CS SSI [8].

The incidence of surgical site infection raises because of emergence antibiotic resistant pathogens like multi drug-resistant pathogens and methicillin-resistant S.aures. The risk of bacterial infection is five to twenty times higher for mothers who had cesarean delivery than for those who gave birth vaginally [9]. Standard criteria are used to identify patients with post–cesarean section surgical site infection (Post-CS SSI). These include purulent discharge from the incision site and the presence of clinical signs and symptoms, such as redness, swelling, pain around the surgical site, and fever [10].

Staphylococcus aureus (S. aureus) was the most frequently isolated pathogen from post–cesarean section surgical site infections (30.4%). Other commonly identified organisms included coagulase-negative staphylococci (CoNS) (11.7%), Escherichia coli (9.4%), Enterococcus faecalis (5.9%), Pseudomonas aeruginosa (5.5%), Enterobacter species (4.0%), and Klebsiella species (4.0%) [11]. Post-CS SSI contributes to infection-associated costs result from prolonged hospitalization, treatment and other medical expenses [12].

Antimicrobial resistance (AMR) is the most critical public health challenge and 1.27 million global deaths occurred due to the bacterial AMR and contributed to 4.95 million deaths in 2019 [13]. Most bacteria develop a resistance to antimicrobial agents; this is because of the misuse of drugs and the bacteria’s nature, which enable them to survive exposure to antibiotics and continue grow [14]. Infections caused by antimicrobial resistant organisms require the use second and third line drugs for treatment, which can negatively affect patient outcomes, lead to organ failure, and prolonged recovery periods lasting several months [15].

There are major gaps in the study area, including a lack of adequate data; major bacterial pathogens responsible for post–cesarean section surgical site infection (Post-CS SSI) and the patterns of antimicrobial resistance are not well identified. In addition, the contributing risk factors have not been adequately documented. As a result, empirical and blind antibiotic therapies are very common in clinical practice. Therefore, the purpose of this study was to identify major microorganisms that are responsible for Post-CS SSI, antimicrobial susceptibility pattern, assess associated risk factors and evaluate the cost expenditure related to Post-CS SSI.

Methods and materials

Study design, setting, period and population

Multi center hospital-based prospective study was conducted from January 01 to March 01, 2025 in two cities found in the Eastern region of Ethiopia. All pregnant women who underwent cesarean section at Hiwot Fana Specialized University Hospital, Dil Chora Referral Hospital, Sabian General Hospital, and Dechatu Health center were study participants. All pregnant women who delivered by cesarean section were included and followed to determine whether they developed surgical site infection while, pregnant women who were not volunteered to participate, took antibiotics within 7 days before surgery and those with evidence of pre-existing infections at the time of cesarean section were excluded from our study.

Study variables

Dependent variables were Post-cesarean surgical site infection (post-CS SSI). Secondary outcomes included bacterial isolates, antimicrobial susceptibility patterns, and costs. Independent variables were age, residence educational status, marital status, occupation, monthly income, Body Mass index (BMI), anemia, pregnancy induced hypertension, gestational DM, urinary tract Infection, post-operative hemoglobin, hospital stays, parity, antenatal care, follow up, previous CS, fetal weight, and type of CS.

Sample size calculation and sampling technique

Sample size is determined by using a single population proportion sample size calculation, with a value of P taken (50%).

n= (z ∞∕2)²*p (1-p)/d² were n=sample size, z = statistic for level of confidence interval 95%.z score = 1.96, p= estimated prevalence 50%, d= precision 5% = z² p*(1-P)/d² = 1.96²x 0.5(1-0.5)/0.05²=384 and to get the final sample size: Assuming 10% non-response rate: n/(1–10% non-respondent) 384/ (1-0.1) = 384/0.9 = 426.6 ~ 427. This study used a convenient sampling technique and proportional allocation formula was used to allocate sample size based on the average monthly number of pregnant women delivered by CS in each hospital (Fig. 1).

Fig. 1.

Schematic presentation of sampling procedure and sample size allocation for Health Facilities in Eastern, Ethiopia, 2025

Data collection and interpretation

8 Nurse and 4 physicians were trained for data collection and data was collected following written consent from each participant. Participants were asked to give their consent if they are willing to participate in the research after we explained the aim of the study to them. Next, a nurse employed a semi-structured questionnaire to gather clinical and socio-demographic data from all pregnant women delivered by cesarean section and were followed up by structured telephone interviews at 7, 14, and 30 days post-cesarean section, with a maximum of three contact attempts during the 30 day follow-up period. The follow-up completion rate was 100%. After that, patients with post-CS SSI were diagnosed by attending obstetrician based on the presence of purulent discharge from the incision site or a clinical diagnosis of infection within 30 days after surgery. A wound sample taken by physician and midwife nurses using sterile cotton swabs. It was gathered prior to wound cleansing, labeled, and delivered to the lab for further analysis in less than an hour. We took care to prevent cross-contamination at every turn. Then information’s regarding financial costs was collected from the hospital finance and hospital liaisons. The financial cost of mothers who had not developed Post-CS SSI was compared with the financial loss of due to Post-CS SSI. The samples were transported by STUART media to Hiwot Fana Specialized University Hospital (HFSUH).

Isolation and identification of bacteria

Pus sample was collected using a sterile swab from the infected site. The swab samples were inoculated in MacConkey and blood agar medium. A candle jar was used to incubate the culture media at 37 °C for 24 h. The microorganisms were isolated based on colony morphology and gram stain. The obtained pure colonies were used for biochemical tests, antibiotic sensitivity test, and implementing the suggested standard operating procedures.

Antimicrobial Susceptibility Tests (AST)

Antimicrobial susceptibility testing (AST) were done by using the Kirby–Bauer disk diffusion method on Mueller–Hinton agar according to the Clinical and Laboratory Standards Institute (CLSI) M100, 34th edition (2024). Bacterial inoculum was standardized to 0.5 McFarland turbidity and incubated at 35–37 °C for 16–18 h. Zone diameters were measured in millimeters and interpreted as Susceptible (S), Intermediate (I), or Resistant (R) according to CLSI 2024 breakpoints.

According to the CLSI M100, 34th edition (2024) guidelines, for Enterobacterales isolates the following antibiotic discs were used: AMP–Ampicillin (10 µg), CZ–Cefazolin (30 µg), CRO–Ceftriaxone (30 µg) or CTX–Cefotaxime (30 µg), AMC–Amoxicillin–clavulanate (20/10 µg), SAM–Ampicillin–sulbactam (10/10 µg), CN–Gentamicin (10 µg), TOB–Tobramycin (10 µg), CIP–Ciprofloxacin (5 µg), SXT–Trimethoprim–sulfamethoxazole (1.25/23.75 µg), TE–Tetracycline (30 µg), MEM–Meropenem (10 µg), and IPM–Imipenem (10 µg). For Pseudomonas aeruginosa isolates, the following antibiotic discs were used: CAZ–Ceftazidime (30 µg), CPM–Cefepime (30 µg), CIP–Ciprofloxacin (5 µg), MEM–Meropenem (10 µg), and IPM–Imipenem (10 µg). For Staphylococcus spp isolates, the following antibiotic discs were used: P–Penicillin (10 units), E–Erythromycin (15 µg), CD–Clindamycin (2 µg), DO–Doxycycline (30 µg), TE–Tetracycline (30 µg), and SXT–Trimethoprim–sulfamethoxazole (1.25/23.75 µg). For Enterococcus spp. isolates, the following antibiotic discs were used: CIP-Ciprofloxacin(5 µg), AMP–Ampicillin (10 µg), P–Penicillin (10 units), LVX–Levofloxacin (5 µg), and TE–Tetracycline (30 µg) [16].

Data quality assurance and quality control

CLSI quality control requirements were followed to confirm that media fulfills Standard Operating Procedure [SOP]. Visual examinations for contamination, uneven fill, hemolysis, bubbles, freezing evidence, and fractures in the media or plastic Petri dishes were carried out. Quality control was carried out to verify the quality of mediums. Before being used, every fresh lot were undergo quality control testing using standard strains of E. coli [ATCC 25922], P. aeruginosa [ATCC 27853], K.peumoniae [ATCC 700603], E. faecalis [ATCC 29212 or 33186], and, S. aureus [ATCC 25923]. A pretest that was given to 5% of participants was used to evaluate a questioner for completeness, readability, and ease of understanding. The SOP’s were followed for collecting the samples. Data quality was carefully followed prior to analysis.

Before analysis, the data was entered into IBM-SPSS version 26. The descriptive data, like frequency, percentage, mean and standard deviation were calculated. Mann–Whitney U test were applied to compare median (IQR) of costs for treatment, laboratory and hospital admission. Bi-variate and multivariate logistic regression analyses using forward conditional method were used to assess the possible risk factors of post-cesarean surgical site infection.

The level of significance P value < 0.25 in bi-variate analysis were included in multivariate logistic regression [17]. Odds ratio with 95% confidence interval was calculated to determine degree of association between dependent and independent variables. A P-value below 0.05 was considered statistically significant for all cases. The research outcomes reported in words, charts, graphs, and tables.

Operational definitions

Post-cesarean surgical site infection

the presence of purulent discharge from the incision site or a clinical diagnosis of infection by the attending physician within 30 days after surgery.

Cesarean delivery

an operational procedure used to give birth via an incision in the abdomen and uterus.

Multi-drug resistance

is defined as non-susceptibility to at least one agent in three or more antimicrobial categories.

Financial cost

The total amount of cost needed from the hospital to treat SSI infection following CS delivery.

Cesarean section infection

presence of infection at the site of surgery following cesarean delivery.

Results

Descriptive characteristics of study participants

The research was carried out on a total of 427 pregnant women who gave birth by cesarean section were included. Of these, 56 (13.1%) developed post cesarean wound infection. Most of the participants were in the age group of 18–27 years (250, 58.5%) with a mean age of 26.9 (SD ± 5.34) years. Many of the respondents 277 (64.9%) lived in urban area. A total of 172 (40.3%) participants have completed higher education, 335 (78.5%) married and 220 (51.5%) housewives. Most of the participants, 229 (53.6%), had monthly income ranging from 1501 to 5000 birr. More than half of the respondents 267 (62.5%) didn’t engage in physical exercise, 285 (66.7%) had never consumed alcohol and 305 (71.4%) never smoked cigarettes (Table 1).

Table 1.

Sociology-demographic characteristics of women who gave birth by cesarean section at public hospitals in Eastern, Ethiopia 2025, n = 427

Variable	Category	Frequency	Percent (%)
Age group in years	18–27	250	58.5
	28–37	163	38.2
	> 37	14	3.3
Residence	Urban	277	64.9
	Rural	150	35.1
Occupation	Housewife	220	51.5
	Government employee	101	23.7
	Private business owner	66	15.5
	Student	40	9.4
Educational background	No formal education	56	13.1
	Primary education	67	15.7
	Second education	132	30.9
	Higher education	172	40.3
Marital status	Married	335	78.5
	Divorced	35	8.2
	Single	51	11.9
	Widowed	6	1.4
Monthly income in birr ($)	< 1500 (11)	48	11.2
	1501–5000 (11-36.6)	229	53.6
	5001–10,000 (36.6–73.5)	132	30.9
	> 100,001 (73.5)	18	4.2
Habit of physical exercise	Never	267	62.5
	Sometimes	130	30.4
	Regularly	30	7
Alcohol drinking habit	Never	285	66.7
	Occasionally	126	29.5
	Regularly	16	3.7
Smoking habit	Never	305	71.4
	Occasionally	108	25.3
	Regularly	14	3.3

Most of the respondents, 220 (51.5%), had BMI greater than 25 kg/ m². Among the study participants, 139 (32.6%) had anemia and only 36 mothers (8.4%) had gestational diabetic mellitus. Forty (9.4%) of participants had pregnancy induced hypertension and 74 (17.3%) had a history of urinary tract infection. More than half of the respondents, 239 (56%), had hemoglobin levels less than 11gm/dl after operation, and 76 (17.8%) of mothers had a prolonged hospital stay of more than 7 days (Table 2).

Table 2.

Clinical characteristics of women who gave birth by cesarean section at public hospitals in Eastern, Ethiopia 2025, n = 427

Variable	Category	Frequency	Percent%
Body mass index	> 25 Kg/ m2	220	51.5
	< 25 kg/ m2	207	48.5
Anemia	Yes	139	32.6
	No	288	67.4
Pregnancy induced hypertension	Yes	40	9.4
	No	387	90.6
Gestational DM	Yes	36	8.4
	No	391	91.6
Urinary tract Infection	Yes	74	17.3
	No	353	82.7
Post-operative hemoglobin	< 11gm/dl	239	56
	> 11gm/dl	188	44
Hospital stays	< 7days	351	82.2
	> 7days	76	17.8

Out of 427 mothers, 238 were multi-para, 180(42.2%) primipara and 9(2.1%) were grand multi-para. Majority of the participants 373(87.3%) had a follow up care in health facilities and 240(56.2%) had a previous CS scar. The mean fetal weight was 3400 gm. The minimum and maximum birth weights were 1700 gm and 5200 gm. About 251(58.8%) of mothers had emergency surgery and 176(41.2%) had elective surgery. Based on the type of abdominal incision, 292(68.4%) was transverse incision and 135(31.6%) was vertical incision. Less than half of the respondents 146(34.2%) had rupture of membrane before CS (Table 3).

Table 3.

Obstetric characteristics of women who gave birth Cesarean section at public hospitals in Eastern, Ethiopia 2025, n = 427

Variable	Category	Frequency	Percent%
Parity	Primipara	180	42.2
	Multipara	238	55.7
	Grand multipara	9	2.1
Antenatal care follow up	Yes	373	87.4
	No	54	12.6
Previous CS	Yes	240	56.2
	No	187	43.8
Fetal weight	< 2400 gm	15	3.5
	2400-4000gm	386	90.4
	> 4000gm	26	6.1
Type of CS	Emergency	251	58.8
	Elective	176	41.2
Incision type	Transverse	292	68.4
	Vertical	135	31.6
Premature rupture of membrane	Yes	146	34.2
	No	281	65.8

Isolation of pathogenic bacteria from post-CS SSI

A total of 60 pus specimens were collected from the wound site and processed during the study period. Of these, 56 pathogenic bacteria were isolated and the remaining 4 specimens had no bacteria growth. Out of 56, 31 (55.35%) were gram-positive and 25 (44.9%) were gram-negative. Among gram-positive bacteria, Staphylococcus aureus 27 (48.2%) was a predominant bacteria. The most common bacteria isolated from gram-negative was 10(17.8%) k.pneumonia, 8 (14.02%) E.coli, and 6 (10.71%) Citrobacter spp. The least isolated bacteria were Enterococcus spp, and Pseudomonas spp were 4 (7.4%), 1 (1.78%) respectively (Table 4).

Table 4.

Isolation of pathogenic bacteria from post-CS SSI at public hospitals in Eastern, Ethiopia 2025, n = 56

Category	Bacterial isolate	Frequency	Percent (%)
Gram-positive	S, aureus	27	48.21
	Enterococus spp	4	7.14
	Total	31	55.35
Gram-negative	k.pneumoniae	10	17.8
	Pseudomonas spp	1	1.78
	E.coli	8	14.2
	Citrobacter spp	6	10.71
	Total	25	44.49

Cost analysis for post-CS SSI

The result indicated that the overall median costs (Ethiopian Birr) of patients with post-CC SSI were 10,071(738) compared to patients without post-CS SSI 5,583 (1,446). The median (IQR) value of medication costs among women who had developed SSI was 6161.50(551), laboratory costs 894(126), and hospital admission costs 3073(357). Based on the independent sample Mann-Whitney U test, the distribution of treatment costs, laboratory costs, and hospital admission costs among women who developed SSI and those who had not developed SSI were statistically significant (p < 0.001) (Fig. 2) (Table 5).

Fig. 2.

Box plot of cost among mothers who had SSI and who had not at public hospitals in Eastern Ethiopia 2025, n = 427

Table 5.

Cost analysis for post-CS SSI at public hospitals in Eastern, Ethiopia 2025, n = 427

Cost for	SSI		P value
	Yes (N = 56), Median(IQR)	No (N = 371), Median ( IQR)
Laboratory	894(126)	540 (219)	< 0.001
Treatment	6161.50 (551)	3334 (1757)	< 0.001
Hospital admission	3073 (357)	1600 (579)	< 0.001
Total cost	10,071 (738)	5583 (1,446)	< 0.001

Factors associated with post-CS SSI

The level of significance P value < 0.25 in bi-variate analysis were included in multivariate logistic regression. Multivariate logistic regression contained residence, BMI, prior CS, type of CS, rupture of membrane before surgery, anemia after surgery, and extended hospital stays were strong association with post-CS SSI at p ≤ 0.05. Mothers from rural areas were 2.37 times more likely to acquire SSI compared to those mothers from urban areas (AOR = 2.53, 95% CI: 1.308, 4.96). Mothers with previous CS scar were 3.916 times more likely to have SSI than mothers with no scar (AOR = 3.916, 95% CI: 1.78, 8.54). Mothers who stayed in the hospital for more than 7 days were significantly associated with post-CS SSI by 5.86 in contrast to those who hadn’t (AOR = 5.86, 95% CI: 2.56, 13.43). A two-fold association of post-CS SSI was observed in women who had post-operative hemoglobin less than 11 g/dL. Post-operative hemoglobin and length of hospital stay were measured immediately after surgery and prior to SSI onset. Model fitness and multi-col-linearity coefficient were performed and overall p value was 0.362 and VIF value close to 1.00 (Table 6).

Table 6.

Factor associated with post- CS SSI at public hospitals in Eastern, Ethiopia 2025, n = 427

Covariates	Category	SSI		Bi-variate Analysis		Multivariate Analysis
		Yes	No	COR (95% CI)	P	AOR(95% CI)	P
Residence	Rural	30	120	2.41 (1.36–4.26)	0.002	2.537(1.308–4.96)	0.006
	Urban	26	251	1		1
BMI	> 25Kg/m2	41	179	2.93(1.57–5.48)	0.001	3.99(1.92–8.30)	< 0.001
	< 25 kg/m2	15	192	1		1
Previous CS	Yes	45	195	3.69(1.852–7.361)	< 0.001	3.915(1.78–8.54)	0.001
	No	11	176	1		1
Type of CS	Emergency	42	201	2.54(1.472–4.53)	0.002	2.745(1.32–5.71)	0.007
	Elective	14	170	1		1
Premature ROM	Yes	33	104	3.68(2.0-6.78)	< 0.001	3.55(1.8–7.03)	< 0.001
	No	23	267	1		1
Post-OR Hg	< 11 mg/dl	43	184	3.35(1.72–6.52)	< 0.001	2.53(1.19–5.361)	0.015
	> 11 mg/dl	13	187	1		1
Hospital stay	< 7 days	40	334	1		1
	> 7 days	16	37	3.61(1.98–6.56)	< 0.001	5.86(2.56–13.43)	< 0.001

Antibacterial resistance pattern for Gram-positive bacteria

Gram-positive organism highly resistant to penicillin, tetracycline, cefotaxime, trimethoprim-sulfamethoxazole, and ciprofloxacin were 71.4%, 58.3%, 73.6%, 63.6% and 50% respectively. In contrast, clindamycin (55%), and linezolid (100%) were susceptible to gram-positive organism (Table 7).

Table 7.

Antimicrobial susceptibility test for Gram-positive bacteria among women with post-cesarean surgical site infections at public hospitals in Eastern, Ethiopia 2025, n = 56

List of antibiotics	AST	Isolated Gram-positive bacteria from post-CS wound infections N (%)
		S.aureus N (%)	Enterococus Spp. N (%)	Total N (%)
CTX	S	5(26.3)	NA	5(26.3)
	I	NA	NA	NA
	R	14(73.6)	NA	14(73.6)
CIP	S	9(40.9)	3(75)	12(46.1)
	I	1(4.5)	NA	1(3.8)
	R	12(54.5)	1(25)	13(50)
CD	S	11(55)	NA	11(55)
	I	NA	NA	NA
	R	9(45)	NA	9(45)
GEN	S	1(50)	NA	1(33.3)
	I	NA	NA	NA
	R	1(50)	1(100)	2(66.6)
P	S	4(21.5)	2(100)	6(28.5)
	I	NA	NA	NA
	R	15(78.9)	NA	15(71.4)
TE	S	8(38.9)	NA	8(33.3)
	I	NA	2(66.6)	2(8.3)
	R	13(61.9)	1(33.3)	14(58.3)
LNZ	S	3(100)	NA	3(100)
	I	NA	NA	NA
	R	NA	NA	NA
LVX	S	3(21.4)	2(66.6)	5(29.4)
	I	2(14.2)	NA	2(11.7)
	R	9(64.2)	1(33.3)	10(58.8)
SXT	S	7(33.3)	NA	7(31.81)
	I	NA	1(100)	1(4.54)
	R	14(66.6)	NA	14(63.6)

*CIP: ciprofloxacin, GEN: gentamycin, TE: tetracycline, LZ: linezolid, SXT: trimethoprim-sulfamethoxazole, LVX: levofloxacin, CTX: cefotaxime CD: clindamycin, P: penicillin and NA: Not applicable.

Antibacterial resistance pattern for Gram-negative bacteria

Gram-negative bacteria isolates susceptible to ciprofloxacin, ceftazidime, Imipenem, Ertapenem, and Meropenem were 53.8%, 64.2%, 92.8%, 94.4%, and 95% respectively. In contrast, trimethoprim-sulfamethoxazole (88.8%), tetracycline (83.3%), ceftriaxone (88.8%), cefotaxime (66.6%), and cefuroxime (66.6%) Amoxicillin/ clavulanic acid (46.6%), cefepime (47.1%) were highly resistant to gram-negative bacteria (Table 8).

Table 8.

Antimicrobial susceptibility test for Gram-negative bacteria among women with post-cesarean surgical site infections at public hospitals in Eastern, Ethiopia 2025, n = 56

Antibiotics	AST	Isolated Gram-negative bacteria from post-CS wound infections N (%)
		Klebsella spp. N (%)	Enterobacter spp N (%)	Citrobacter spp N (%)	Pseudomonas spp N (%)	Total N (%)
AMC	S	1(12.5)	3(60)	1(33.3)	NA	5(33.3)
	I	1(12.5)	1(20)	2(66.6)	NA	4(26.6)
	R	6(75)	1(20)	NA	NA	7(46.6)
CAZ	S	7(77.7)	NA	1(25)	1(100)	9(64.2)
	I	NA	NA	2(50)	NA	2(14.2)
	R	2(22.2)	NA	1(25)	NA	3(21.4)
CPM	S	5(71.4)	NA	1(16.6)	NA	6(35.2)
	I	1(14.2)	NA	2(33.3)	NA	3(17.6)
	R	1(14.2)	3(100)	3(50)	1(100)	8(47.01)
CTR	S	1(11.1)	NA	1(16.6)	NA	2(11.1)
	I	NA	NA	NA	NA	NA
	R	8(88.8)	3(100)	5(83.3)	NA	16(88.8)
CTX	S	1(33.3)	3(60)	NA	NA	4(33.3)
	I	NA	NA	NA	NA	NA
	R	2(66.6)	2(40)	4(100)	NA	8(66.6)
CXM	S	1(50)	2(40)	NA	NA	3(33.3)
	I	NA	NA	NA	NA	NA
	R	1(50)	3(60)	2(100)	NA	6(66.6)
CIP	S	6(66.6)	NA	NA	1(100)	7(53.8)
	I	2(22.2)	NA	NA	NA	2(15.3)
	R	1(11.1)	3(100)	NA	NA	4(30.7)
IPM	S	5(83.3)	4(100)	4(100)	NA	13(92.8)
	I	NA	NA	NA	NA	NA
	R	1(16.6)	NA	NA	NA	1(7.14)
MEM	S	5(83.3)	7(100)	7(100)	1(100)	19(95)
	I	NA	NA	NA	NA	NA
	R	1(16.6)	NA	NA	NA	1(5)
LVX	S	6(85.7)	3(60)	1(50)	NA	10(71.4)
	I	NA	NA	NA	NA	NA
	R	1(14.2)	2(40)	1(50)	NA	4(28.5
SXT	S	1(25)	NA	NA	NA	1(11.1)
	I	NA	NA	NA	NA	NA
	R	3(75)	3(100)	2(100)	NA	8(88.8)
EPM	S	6(85.7)	7(100)	4(100)	NA	17(94.4)
	I	NA	NA	NA	NA	NA
	R	1(14.2)	NA	NA	NA	1(5.5)
TE	S	1(25)	NA	NA	NA	1(16.6)
	I	NA	NA	NA	NA	NA
	R	3(75)	2(100)	NA	NA	5(83.3)

*CTR: ceftriaxone, CAZ: ceftazidime, CIP: ciprofloxacin, AMC: amoxicillin-clavulanic acid, CPM: cefepime, IPM: imipenem, CTX: cefotaxime, CXM: cefuroxime, MEM: meropenem, TE: tetracycline, LVX: levofloxacin, SXT: trimethoprim-sulfamethoxazole, EPM: Ertapenem and NA: Not applicable.

Discussion

Post cesarean wound infection rise maternal mortality, morbidity, prolonged hospital stay, and increase health care cost [7]. In this study the major etiologic agent that significantly contributes to the cause the maternal mortality and morbidity were isolated. This will help to decrease the occurrence and effect of post cesarean wound infection.

The incidence of Post-CS SSI in this study was 56 (13.1%). It is aligned with previous researches undertaken in Harar, Ethiopia (12.3%), Nigeria (12.5%), and Dhulikhel Hospital, Nepal (12.6%) [18–20]. The WHO surgical site infection rate guidelines were up to 20% in Africa, which is in line with this study [21]. According to this study, the incidence of post-CS SSI was higher in comparison to previous research undertaken in Assela, Ethiopia (9.4%), Hawassa University Teaching Hospital, Ethiopia (11%), Estonian University Hospital (6.2%), and Regional Referral Hospital, Oman (2.66%) [22–25]. This variation in the incidence of post-CS SSI might result from socioeconomic status, study area, health care delivery system, and study population. The difference may arise from lack of adequate sterilization technique, and quality of surgical care provision.

Premature rupture of membrane was significantly associated (p < 0.001) with post-CS SSI. Mothers who had rupture of membrane before CS contribute to high chance of developing SSI by three times more than who had not (AOR = 3.55, CI: 1.8–7.03). It is aligned with previous research done in Nigeria (AOR = 4.45) and US (AOR = 3.0; 95% CI, (3.24–3.5) [26, 27]. The amniotic fluid in pregnant women played as a barrier for pathogenic bacteria but if the fetal membrane ruptured early, the protective effect of the fluid gradually decreases over time.The pathogenic bacteria get access to enter in amniotic cavity through cervical canal may result in SSI.

Mothers from rural areas were 2.537 times more likely to acquire SSI compared to those mothers from urban areas (AOR = 2.537, 95% CI: 1.308, 4.96). There was a study undertaken in Tigray and US also shown significant association [26, 28]. This may be caused by limited access to health care and poor hygiene affects a good practice throughout the surgery process.

This study showed that the risk of developing Post-CS SSI after CS were 2.7 times higher among women who had emergency CS compared to those had elective CS (AOR = 2.745, 95% CI: 1.32–5.71). Similar findings were reported from Nigeria showed that 11% who had emergency procedure got post-CS SSI than elective CS [29]. This could be caused by limited time for preparation can lead to poor sterility condition and imposing the patient at greater risk of bacterial contamination and high number of cesarean section procedures were performed daily.

A significant correlation was found between post-CS SSI and obesity. The study revealed that having a body mass index more than 25 kg/m2 has four times higher risk for having post-CS SSI (AOR = 3.99, 95% CI: 1.92–8.30). Current study align with a prospective study performed in Iraq [30]. This might be due to thick subcutaneous tissue, impaired immunity, and limited penetration of prophylactic antibiotics in adipose tissue.

This study also found that mothers with post-operative hemoglobin level < 11 g/dl were significantly associated with post-CS SSI (AOR = 2.53, 95% CI: 1.19–5.361). This research supported by the studies undertaken in Nigeria and Ethiopia [19, 31]. This is because decrease amount of hemoglobin results impaired transportation of oxygen which leads to hinder wound healing and weakened immune system.

A hospital stay longer than 7 days was significantly associated with post-CS SSI (AOR = 5.86, 95% CI: 2.56–13.43). This study aligns with research done in different settings [18, 32, 33]. This might be due to the long the mothers stay the more to get infection because hospital areas assumed to be contaminated by medical staff, patients, and attendants. In addition, women’s who had previous scar is more likely to develop post-CS SSI than those had not [34, 35]. This might be due to presence of prior scars had intraoperative adhesion, weaker scar and poor healing.

Previous studies showed that hospitalization was prolonged for mothers who developed post-CS SSI compared to those who had not [36]. This cause significant increase in cost of the following medications, laboratory, and hospital admissions. The median cost of treatment with post-CS SSI was 6161.5 birr and 3334 birr for patients without SSI. Likewise, Median cost on hospital admission were 3073 birr with SSI compare to 1600 birr patients without SSI. Laboratory cost median differed in mothers with SSI 894 birr to mothers without SSI 540 birr. The cost of treatment, laboratory, and hospital admission cost were significantly associated with post-CS SSI p < 0.001, p < 0.001, and p < 0.001 respectively. It agrees with a study done in Germany [36]. The overall median cost for patients who had post-CS SSI was 10,071 birr and was therefore higher than for mothers without SSI 5583 birr( p < 0.001).This findings consistent with a study in Berlin and others [36, 37]. This could be due to patient need additional analysis and care to treat the infection. The increased cost associated with post-cesarean surgical site infections places an additional financial burden on the government.

In current study, Gram-positive organisms were 56.1% and 42.1% were Gram-negative organisms. S.aureus is a predominant from gram-positive organisms by (47.3%) subsequent to K.pneumonia were (17.5%), E.coli (14.3%), Citrobacter (10.5%), Enterococus spp(7.01%), CoNs and Pseudomonas spp were similar(1.75%).

This is supported by the research done in Ethiopia, the most frequently isolated bacteria were S. aureus (41.6%), E. coli (19.8%), K. pneumoniae (13.9%), coagulase-negative Staphylococcus (12.9%), and Enterobacter spp (4%) [38]. Based on research conducted in Pakistan, A total of 153 organisms were identified, of which Staphylococcus aureus (50.32%), followed by Pseudomonas aeruginosa (16.3%), Escherichia coli (14.37%), and Klebsiella pneumoniae (11.76%) [39].

In other previous study, revealed that a high proportion of Gram-negative organism than Gram-positive organisms. According to study done in Ethiopia, 55.9% were accounted for gram negative organisms and 44.1% for gram positive bacteria. Escherichia coli was the major bacteria isolate from gram negatives (24.3%) subsequent to Staphylococcus aureus (23.4%) in gram positives [40]. This difference in the pattern of distribution of bacterial isolates in different setups may be due to diversity of the study participants and inappropriate usage of local antimicrobial agent lead to emergence of bacteria that resist to commonly used antibiotics.

In present study, linezolid (100%), and clindamycin (55%) were susceptible for gram-positive bacteria. The current research is consistent to studies in Ethiopia, and India [41, 42]. Levofloxacin (71.4%), ciprofloxacin (53.8%), Imipenem (92.8%), and ceftazidime (64.2%) were susceptible for isolated bacteria from gram-negative. This aligns with research conducted in India, Nepal, and Ethiopia [42–44]. Many of the gram-negative bacteria were resistant to ceftriaxone(88.8%), cefuroxime(66.6%), amoxicillin/clavulanic acid(46.6%), cefotaxime(66.6%), cefepime(47.01%), trimethoprim-sulfamethoxazole(88.8%), and tetracycline(83.3%), which are consistent with different studies worldwide [10, 45, 46]. This could be due to empirical therapy, improper dosing, and non-prescribed antibiotic use causes the antibiotic to be ineffective for pathogens.

Staphylococcus aureus was the number one bacteria isolated from wound site, which was resistant to Tetracycline, Peniciliin, and trimethoprim-sulfamethoxazole were 61.9%, 78.9%, and 66.6% respectively. This findings is consistent with study undertaken in Bahirdar, Ethiopia showed that the overall resistance rate of Tetracycline, Chloramphenicol, Penicillin and Ampicillin were 62% [47].

E. coli was highly resistant to cefepime (100%), ceftriaxone (100%), ciprofloxacin (100%), and tetracycline (100%). This is in agreement to study done in Oman [25]. K.pneumonia was resistant to amoxicillin/clavulanic acid (75%), ceftriaxone (88.8%), and Tetracycline (75%). This aligns with a study conducted in Tanzania [48]. High incidence of antibiotic resistant occurred because frequent usage of drug without prescription.

Strength and limitation of the study

The data had adequate representation of the study because it was conducted in 3 hospitals and 1 health center, while the limitations were that the study had a one-month follow-up, making it difficult to show cause-and-effect association; exclusion of mothers who did not seek health support despite having mild post-cesarean section infection; and failure to isolate strict anaerobic bacteria and fungi, which could have increased the number of bacterial isolates reported as negative cultures and underestimated the magnitude of post-cesarean section surgical site infection. The use of convenience sampling over a short two-month data collection period may limit the generalization of the findings and introduce potential selection bias.

Conclusion and recommendation

The incidence of post-cesarean wound infection was 13.1%, which is relatively higher in the study area. The most frequently isolated organisms were S.aureus and Enterobacter spp among Gram-positive bacteria, and E.coli, K. pneumoniae, and Citrobacter spp among Gram-negative bacteria. Both gram positive and gram negative bacteria have developed resistant to widely used antibiotics such as tetracycline and trimethoprim-sulfamethoxazole. Patients with multi-drug resistance infections cause an increase in hospital stays and health care costs.

The authors strongly urge strict adherence with post-CS SSI prevention strategies at hospitals and health centers as strict administration of pre and post-operative antibiotics reduce the incidence of SSI. The observed resistance patterns underscore the urgent need for rational antibiotic use, culture-guided therapy, and the implementation of antimicrobial stewardship programs to limit inappropriate prescribing and slow the emergence of drug resistance.

Supplementary Information

Below is the link to the electronic supplementary material.

Abbreviations

AAU

Addis Ababa University

AMR

Antimicrobial Resistance

AST

Antimicrobial sensitivity test

BMI

Body mass index

CDC

Center of Disease Control

CS

Cesarean section

CLSI

Clinical laboratory Standards Institute

CSI

Cesarean section infection

DRERC

Departmental research and ethical review committee

LSCS

Lower segment Cesarean section

MHA

Muller Hinton agar

MOH

Ministry of Health

Post-CS SSI

Post cesarean section surgical site infection

SOP

Standard Operating Procedure

IQR

Interquartile range

Author contributions

AF was the principal investigator who participated in project coordination, data quality assurance, method validation, conceptualization of the study, drafted the manuscript, performed statistical analysis and participated in the data collection and laboratory testing of samples; BZ, AD and MM participated in method validation, writing and statistical analysis, reviewing and editing the study; and AH and KD participated in data collection, statistical analysis and writing.

Funding

Addis Ababa University provided funding for this study, which was utilized for data collection and laboratory testing of samples. The study design, statistical analysis, conceptualization and manuscript preparation were performed without the funder’s input.

Data availability

The datasets used or analyzed during the current study are available from the corresponding author upon reasonable request.

Declarations

Ethics approval and consent to participate

Before data collection, written consent was obtained from the Research and Ethics Review Committee (RERC) of Addis Ababa University College of Health Science, Department of Medical Laboratory Science (DRERC/778/24/MLS), and permission letter was submitted to Hiwot Fana Specialized University Hospital, Dil Chora Referral Hospital, Dechatu Health center and Sabian General Hospital. Furthermore, informed written consent was obtained from each study participant before the actual data collection and the purpose of the study was explained to the study participant and they were informed about the information obtained in course investigation will be kept confidential using codes and they do have right to get their results without payment. The test results of study participants were communicated to their attending physician. The study was conducted in accordance with the ethical principles of the Declaration of Helsinki.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.