EVALUATION OF THE PATTERN OF BACTERIAL CONTAMINATION IN MICROBIOLOGICAL LABORATORIES IN RELATION TO CLEANING AND DISINFECTION PRACTICES IN A MAJOR SPECIALIZED HOSPITAL IN SAUDI ARABIA.

Abstract

Background: Microbiology laboratories are critical to modern healthcare but remain vulnerable to bacterial contamination due to constant handling of infectious materials. Inadequate cleaning and disinfection practices can compromise diagnostic accuracy and pose serious risks to laboratory personnel.

Objectives: This study aimed to evaluate the pattern of bacterial contamination in relation to cleaning and disinfection protocols in a microbiology laboratory within a major specialized hospital in Saudi Arabia.

Methods: A cross-sectional study was conducted from September to December 2024. A total of 3,200 surface swab samples were collected from high-touch areas, including workstations, incubators, and equipment handles. Samples were processed using standard microbiological techniques and analyzed via biochemical testing and the VITEK 2 system. The effectiveness of cleaning with 5% sodium hypochlorite was assessed by sampling at different time intervals. Statistical analysis was conducted using SPSS version 25.0.

Results: Of the 3,200 samples, 40% (n=1,280) were culture positive. The most frequently isolated organisms were aerobic spore-forming bacilli (n=248), Staphylococcus aureus (n=210), Escherichia coli (n=152), and Acinetobacter baumannii (n=150). Workstations and incubators showed the highest contamination rates. Polymicrobial growth was observed in over 90% of positive samples. Bacterial recovery significantly decreased after cleaning, demonstrating the effectiveness of disinfection (p < 0.00001).

Conclusion: The findings underscore the importance of consistent and effective cleaning protocols in reducing microbial contamination in laboratory settings. A comprehensive contamination control strategy—including routine disinfection, staff training, environmental monitoring, and strict adherence to biosafety practices—is essential to ensure diagnostic reliability and laboratory safety.