Bacterial profile and antimicrobial susceptibility patterns of isolates from postoperative surgical site infections and hospital environment samples

Abstract

Background: The occurrence of microorganisms especially antimicrobial-resistant bacteria in health facilities can cause infections among admitted patients. This increases the treatment costs, prolonged hospital stays, and significant morbidity and mortality for postoperative patients. Currently, there is insufficient evidence of surgical site infection and multidrug-resistant bacteria. Therefore, continuous surveillance is necessary to guide an appropriate therapy for surgical site infection and the rational use of antimicrobial agents. Thus, this study provides updated information on information about the bacteria, Multi-Drug Resistance bacteria species responsible for postoperative surgical site infection, and the etiologic agents in hospital environments.

Objectives: This study assesses bacterial profile and antimicrobial susceptibility patterns in samples collected from postoperative surgical site infections and the hospital environment at the University of Gondar Comprehensive Specialized Hospital, Gondar; Northwest Ethiopia.

Materials and methods: A cross-sectional study was conducted among patients with postoperative surgical site infections and hospital environment samples from February 1 to April 30, 2020. All postoperative patients suspected of having surgical site infections and hospital environments were included in the study. A total of 202 samples (52 from wounds and 150 from the environment) were examined. Socio-demographic characteristics were collected using a structured questionnaire. Swab samples were obtained and inoculated onto MacConkey agar, Mannitol salt agar, Blood agar plates, and Chocolate agar by rolling the swab over the agar surfaces. The inoculated plates were then incubated at 37 °C for 24 to 48 hours. Air culture samples from Blood agar plates were also incubated at 37 °C for 24 hours. Antimicrobial susceptibility testing was conducted using the disk diffusion method on Muller Hinton agar. Data were entered and analyzed using Statistical Package for the Social Sciences version 20. Descriptive statistics were employed to present the findings through words, percentages, and tables.

Results: Of 52 wound samples from surgical site infection, the most frequent isolates were S. aureus and Klebsiella species, each accounting for 11 cases (20%), followed by E. coli with 10 cases (18.2%). Among the S. aureus isolates, 63.6% were methicillin-resistant. The overall rate of multidrug resistance was 31 cases (56.4%). Regarding hospital environmental samples, of 150 samples, the most commonly identified isolates were coagulase-negative S. aureus with 57 cases (47.5%), followed by S. aureus with 35 cases (29.2%). The overall rate of multidrug resistance was 66 cases (55.0%).

Conclusion: Staphylococcus aureus, Klebsiella species, and E. coli were identified the most prevalent bacteria associated with postoperative surgical site infections, with hospital environments serving as potential reservoirs for these pathogens in the study area. High prevalence rates of methicillin-resistant and multidrug-resistant were observed among both clinical and hospital isolates in this study. However, Amikacin and Clindamycin demonstrated the highest effectiveness in inhibiting the in vitro growth of Gram-negative and Gram-positive bacterial isolates, respectively. Therefore, updating treatment guidelines based on hospital formularies and susceptibility patterns is crucial to prevent the further emergence and spread of multidrug-resistant bacterial pathogens. Additionally, infection prevention practices should be strengthened.