Antibiotic Use and Antibiotic Susceptibility of Common Environmental Bacterial Species in the Intensive Care Unit at Mbarara Regional Referral Hospital, Uganda

Abstract

Background: Environmental contamination in intensive care units (ICUs) is a recognized concern due to its potential role as a reservoir for pathogenic and antimicrobial-resistant bacteria. Understanding the extent and patterns of contamination is essential for strengthening infection prevention and control strategies, particularly in resource-limited settings. Methods: A cross-sectional environmental surveillance study was conducted in the ICU of Mbarara Regional Referral Hospital. A total of 34 high-touch surfaces were sampled using sterile pre-moistened swabs over a standardized area. Bacterial identification was based on colony morphology, hemolytic patterns, Gram staining, and microscopic characteristics. Antimicrobial susceptibility testing was performed using the disc diffusion method, with zones of inhibition measured in millimeters and interpreted as sensitive, intermediate, or resistant according to standard guidelines. Results: Of the 34 environmental samples collected, 32 (94.1%) yielded bacterial growth, resulting in a total of 40 isolates. Gram-positive bacteria accounted for 21 isolates (52.5%), while Gram-negative bacteria accounted for 19 isolates (47.5%). Common isolates included Staphylococcus aureus, Klebsiella species, and Escherichia coli. Antimicrobial susceptibility testing revealed varying resistance patterns across commonly used antibiotics, with notable resistance observed among several isolates. Descriptive patient data indicated frequent use of broad-spectrum antibiotics within the ICU. Conclusions: This study demonstrates a high level of bacterial contamination on ICU surfaces, with diverse organisms exhibiting varying antimicrobial resistance patterns. While no direct relationship between environmental contamination and patient infections was established, the findings highlight the importance of maintaining stringent infection prevention and control practices. Further studies incorporating advanced microbiological techniques are recommended to better understand transmission dynamics in ICU settings. The findings highlight the urgent need for strengthened antimicrobial stewardship programs and routine culture and sensitivity testing in resource-limited ICU settings.