Bacterial Contamination, Antibiotic Resistance, and Biofilm Formation on Operating Rooms Surfaces at Jimma Medical Center, Southwest Ethiopia

Background Microbial contamination in hospitals, especially in operating theatres and specialized units, greatly contributes to the increasing number of hospital-acquired infections, which pose high morbidity and mortality risks for post-operative patients. Therefore, this study aimed to assess bacterial colonization on surfaces and in the air of operating rooms at Jimma Medical Centre, southwest Ethiopia. Methods A cross-sectional study was conducted from April to August 2022, during which a total of 239 samples were collected, including 159 swabs from frequently touched surfaces and 80 air samples. Bacterial isolation and identification were performed using standard bacteriological techniques. Antimicrobial susceptibility test was performed using the Kirby-Bauer disc diffusion method. Extended-Spectrum Beta-Lactamase and carbapenemase production were detected using combination disc and modified carbapenem inactivation methods. Methicillin-Resistant Staphylococcus aureus and biofilm formation were identified using cefoxitin discs and a 96-well microtiter plate assay. Data were analyzed using SPSS version 25 descriptive statistics and chi-square test was applied, with p < 0.05 considered statistically significant. Results A total of 243 bacterial isolates were recovered. Gram-positive bacteria were predominant 218/243 (89.7%), with coagulase-negative staphylococci 96/218 (39.5%) and S. aureus 76/218 (31.3%) being the most common. Methicillin resistance was found in 19/76 (25%) of S. aureus and 18/96 (18.8%) of coagulase-negative staphylococci. Among Gram-negative isolates, 6/25 (24.0%) were carbapenemase producers, and 3/14 (21.4%) of Enterobacteriaceae produced ESBL. Overall, 63/243 (25.9%) of isolates were multidrug-resistant, and 34/47 (72.3%) demonstrated biofilm formation. Conclusion The inanimate hospital environments in Jimma Medical Center operating rooms are colonized with potentially pathogenic bacteria and the load of bacteria on surfaces and in the air were higher than standards. It is crucial to maintain strict infection prevention and control measures.