Pattern of antibiotic resistance in surgical site infections in a tertiary care hospital of Nepal

Abstract

Background: Surgical site infection (SSI) is the second most common hospital-acquired infection. The identification of bacterial pathogens and their antibiotic susceptibility pattern is required for the successful treatment of SSI and curb antimicrobial resistance, which is a major threat globally. This study aimed to assess the microbial profile of the organisms causing SSI and their antibiogram in a tertiary care hospital. Methods: This cross-sectional study was conducted at Microbiology Laboratory of tertiary care hospital, from March 2023 to August 2023. Swab or aspirate specimens were collected aseptically from the surgical site and processed for bacterial isolation following standard bacteriological techniques. Gram’s staining and biochemical tests were performed to identify the organisms at the species level. Antimicrobial susceptibility tests were done following Kirby–Bauer’s disc diffusion method. Statistical analysis was performed using SPSS software version16.0. Results: Out of 405 samples, 92 (22.7%) yielded bacterial growth. Eighty-three culture positive cases (90.2%) were monomicrobial while nine (15.7%) had mixed growth of at least two different bacteria. Out of 108 isolates, 43 (39.8%) were gram-positive and 65 (60.2%) were gram-negative bacteria. Escherichia coli (39.8%) was the most commonly isolated organism. All gram-negative isolates were resistant to ceftriaxone followed by amoxicillin-clavulanic acid (94.0%), amoxicillin (94.0%), cefixime (90.7%), and cefepime (89.8%). Similarly, none of the gram-positive isolates were susceptible to ampicillin, amoxicillin, and ampicillin/sulbactam. The most effective drugs against E. coli were imipenem (100%), followed by tigecycline (96%), meropenem (95.1%), chloramphenicol (84%), amikacin (81.5%), and gentamicin (81.5%). Overall prevalence of MDR was 59.3%. Conclusion: Our study demonstrates increased resistance of both gram-positive and gram-negative organisms to commonly used drugs like cephalosporins and even quinolones. Continued surveillance of antimicrobial susceptibility results at local level, dissemination of data, and prescribing the antibiotics accordingly based on culture and sensitivity results are necessary to ameliorate antimicrobial resistance.