Peter Wilson

Introduction. Pseudomonas aeruginosa in healthcare shower waters presents a high risk of infection to immune-suppressed patients; identifying the colonization-status of water outlets is essential in preventing acquisition. Hypothesis/Gap Statement. Testing frequencies may be insufficient to capture presence/absence of contamination in healthcare waters between sampling and remediation activities. Standardization of outlets may facilitate the management and control of P. aeruginosa . Aim. This study aims to monitor shower waters and drains for P. aeruginosa in augmented and non-augmented healthcare settings every 2 weeks for a period of 7 months during remedial actions. Methodology. All shower facilities were standardized to include antimicrobial silver-impregnated showerhead/hose units, hose-length fixed to 0.8 m and replaced every 3 months. Standard hospital manual decontamination/disinfection occurred daily. Thermostatic-mixer-valves (TMVs) were replaced and disinfected if standard remediation unsuccessful. Results. Of 560 shower and drain samples collected over 14 time-points covering 7 months, P. aeruginosa colonized 40 %(4/10; non-augmented) and 80 %(8/10; augmented-care) showers in the first week. For each week elapsed, new outlets became contaminated with P. aeruginosa by 18–19 % ( P <0.001) in shower waters (OR=1.19; CI=1.09–1.31) and drains (OR=1.18; CI=1.09–1.30). P. aeruginosa occurrence in shower water was associated with subsequent colonization of the corresponding drain and vice versa (chi-square; P <0.001) with simult