Bacterial Etiology, Antimicrobial Susceptibility Profile, and Associated Risk Factors of Surgical Site Infections and Blood Stream Infections at Asella Teaching and Referral Hospital, South East Arsi, Ethiopia: Prospective Cohort Study.

Abstract

ABSTRACT Background: Blood Stream Infections (BSIs) are defined as the presence of viable infectious microorganisms in the bloodstream causing clinical illness. Local and regional antimicrobial resistance (AMR) surveillance contributes to national efforts, which in turn support global strategies to combat AMR. A Surgical Site Infection (SSI) is defined as an infection occurring within 30 days after surgery involving the skin, superficial incision, deep soft tissue of the incision. Surgical site infection accounts for one of the common healthcare associated infections occurring both in developed, and developing countries. SSIs continue to be a major cause of postoperative morbidity and mortality despite improvements in aseptic techniques, particularly in settings with limited resources. Objective: To determine bacterial etiology, antimicrobial susceptibility profile and associated risk factors of surgical site infections and blood stream infections at Asella Teaching and Referral Hospital, South East Arsi, Ethiopia. Methods: Prospective cohort study design was conducted from June, 2024 to June, 2025. Overall a total of 314 post operative admitted patients from the obstetrics and gynecology and general surgical wards were included, through consecutive sampling technique. Wound swabs were collected aseptically on the first day when patients presented with clinical evidence of surgical site infections after surgery. Socio-demographic data and clinical samples (Swab and Blood) were collected by using pre-tested standardized questionnaires and aseptic techniques, respectively. Bactreial isolation, and identification were done based on the standard microbiological tests. Phenotypic antimicrobial susceptibility profiles were performed using the Kirby-Bauer disk method. Interpretation of the zone diameters was done following the Clinical and Laboratory Standards Institute guidelines CLSI guideline2025. Data were entered into Epi-info 7, cleaned, exported to Excel 2016, and loaded into SPSS version 26 software for analysis. Descriptive statistics were presented in tables and bar charts, and multivariate regression were done to see any significant association. A p value of less than or equal to 0.05 was considered as the presence of significant association. Results: Out of 314 study participants, 56.4% (n = 177/314) were female, and 43.6% (n=137/314) were male. From surgical ward were 56.7% (n=178/314), from gynecology and obstetrics wards were 43.3% (n=136), with a mean age of 36.1 years (SD ± 15.6). Overall identified SSIs patients those who developed SSI presumptive were 16.6% (n=52/314), from this SSIs confirmed culture positive were 63.5% (n=33/52). Out of a total of culture positive SSI, 60.6% (n=20/33) were developed presumptive BSIs after the follow up. From these presumptive BSI 65% (n=13/20) were confirmed bacterial culture positive in blood culture. Gram-positive bacteria 51.5% (n=17/33), gram-negative were 48.5% (n=16/33). The predominant pathogens were Staphylococcus aureus from wound swabs 30.3 % (n=10/33), followed by Escherichia coli from blood culture 18.2% (n=6/33), from wound swabs culture 9.1% (n=3/33), and a total of sum were 27.3% (n=9/33). Staphylococcus aureus were resistant to Ampicillin 10 (100%) and Gentamicin 4(75%), while gram-negative bacteria showed an overall resistance rate of 48.5% (n=16), with E. coli resistant to cefepime 79% (n=3) and ceftriaxone 98% (n=6). Klebsiella spp were resistant to Cefepime 7(80%) and ceftriaxone 7(100%). Similarly, klebsiella pneumonia were showed resistant to cefepime 2(80%) and trimethoprim sulfamethoxazole 2(80%). Almost all identified gram-negative bacteria showed susceptible to Meropenem, Imipenem, Ertapenem, and Amikacin. Multidrug resistance was observed in 56% (n=14) of isolates, with 72% (n=18) resistant to more than three antimicrobial classes. CBC parameters likes WBC, Lymphocyte, Neutrophil, Platelets for SSI and BSI Platelet were compared platelets were significantly P<0.01 associtated with BSI. Emergency surgical procedure was statistically significant when compared to other independent variables of risk factors with (P<0.05), for blood stream infections, BSI, [(AOR=4.9, 95% CI (0.07338_7.9409]; p=0.047). The multivariate analysis show that diabetes mellitus, and smoking cigarette, alcohol intake (P<0.05) so those variables were statistically significant for SSIs and BSIs [AOR=1.66, 95% CI (0.36_7.6)]; P=0.01, AOR=6.1, 95% CI (1.1_36.7); P=0.04, and AOR=6.0, 95% CI (1.1_31.90); P=0.034)] respectively. Conclusion and Recommendation: SSIs and BSIs were predominantly caused by Staphylococcus aureus 30.5% and Escherichia coli 27.3%, respectively. To assess SSI and BSIs incidence rates, bacterial profiles, and antibiotic susceptibility patterns. Key words: Antimicrobial Susceptibility, Antibiotic Resistance, MDR, Surgical Site Infection, Blood stream infections, Ethiopia