A SYSTEMS BASED APPROACH TO MICROBIOLOGICAL QUALITY ASSESSMENT IN A HEALTHCARE FACILITY’S WATER DISTRIBUTION NETWORK: A CASE STUDY

Background: Water distribution systems within healthcare facilities are complex ecosystems that can harbor opportunistic pathogens, posing a significant risk to patient safety. Ensuring the microbiological quality of water requires rigorous monitoring and a deep understanding of the entire system, from source to point-of-use. This study undertakes a comprehensive statistical analysis of microbiological data from a healthcare facility’s water treatment and distribution network to identify contamination hotspots, evaluate the efficacy of critical treatment barriers, and map potential contamination pathways. Methods: This retrospective case study analyzed heterotrophic plate count (HPC) data collected from 29 distinct sampling points throughout a healthcare facility’s water system. The points represented various stages, including municipal source water, intermediate treatment steps (softening, ultrafiltration, reverse osmosis), storage tanks, and multiple points-of-use. Non-parametric statistical methods were employed due to the non-normal distribution of microbial data. A Kruskal-Wallis test with Dunn's post-hoc analysis was used to compare microbial loads across all sampling points. A focused Mann-Whitney U test was performed to assess the performance of the ultrafiltration (UF) unit. Results: The analysis revealed significant variability in microbiological quality throughout the system (Kruskal-Wallis, p<0.0001). One point-of-use and a pre-UF exhibited high median microbial counts and extreme variability, indicating chronic contamination and potential biofilm proliferation. Critically, the ultrafiltration unit failed to demonstrate a statistically significant reduction in microbial load between the pre-filter. Conclusion: The data reveals variability in microbiological levels across the water system, suggesting that the ultrafiltration barrier's performance is a significant factor influencing downstream water quality. The data points to systemic issues, likely involving widespread biofilm, that compromise water quality at the points-of-use. Peer Review History: Received 1 June 2025; Reviewed 8 July 2025; Accepted 14 August; Available online 15 September 2025 Academic Editor: Dr. Tamer Elhabibi, Suez Canal University, Egypt, [email protected] Reviewers: Dr. Gülay B Anadolu, Anadolu University, Eskisehir, Turkey, [email protected] Prof. Dr. A. Hakan AKTAŞ, Süleyman Demirel University, Faculty of Science and Art, Department of Chemistry, Isparta-Turkey, [email protected]