Evaluating the Effectiveness of Sterilization Protocols and Microbial Contamination in Operation Theatres: A Four-Year Repeated Cross-Sectional Surveillance Study

Background: Effective sterilization and decontamination of operation theatres (OTs) are critical for patient safety and prevention of healthcare-associated infections. Environmental contamination of OTs may arise from multiple sources, including inadequately disinfected surfaces, airborne microorganisms, staff movement, and unauthorized entry of non-medical personnel. Objective: To monitor microbial contamination trends in operation theatres over a four-year period and to evaluate the effectiveness of decontamination and access-control practices in reducing environmental microbial load. Methodology: A repeated cross-sectional surveillance study was conducted from April 2020 to April 2024 in the Microbiology Section of the Pathology Department, Quaid-e-Azam Medical College, Bahawalpur. Quarterly random sampling was performed across all active operation theatres. Environmental samples were collected from air, floors, walls, operating tables, washbasins, and anesthesia trolleys using standardized aseptic techniques. Samples were cultured on blood agar and MacConkey agar, incubated at 37 °C, and analyzed for microbial growth. Identification was performed using Gram staining and biochemical tests. Results: Out of 2,212 environmental samples, 913 (43.2%) showed microbial growth. Staphylococcus aureus was the most frequently isolated organism, followed by Escherichia coli, Pseudomonas spp., and Klebsiella spp. Floors and air samples demonstrated the highest contamination rates. A steady and sustained reduction in microbial contamination was observed over the study period, with marked improvement following reinforcement of sterilization protocols and restriction of unauthorized access. Conclusion: The findings demonstrate that strict adherence to decontamination protocols, controlled access to operation theatres, and continuous microbiological surveillance significantly reduce environmental contamination. Keywords: Decontamination, Infection control, Microbial contamination, Operation theatres, Surveillance.