Building water as a source of healthcare associated infections

Introduction: Drinking water has been described as the most underestimated and potentially controllable source of healthcare associated infections (HAIs). It is estimated that water accounts for 20% of HAIs and in the USA 20-50% of nosocomial Pseudomonas aeruginosa cases are waterborne. Methods: We have conducted several studies investigating factors that promote the prevalence of waterborne pathogens in hospitals.1)Hospital water and biofilm samples were analysed using culture, flow cytometry and molecular techniques to investigate the relationships between Legionella, Pseudomonas, Acanthamoeba, Vermamoeba with changes in water flow and the temperature was measured using the Enware Smart Flow monitoring system.2)16S rRNA sequencing was conducted to examine how the hospital water and biofilm microbiome was influenced by incoming water and changes in water flow and temperature arising through intermittent usage.3)A model plumbing system was established and used to examine the influence of brass versus stainless steel plumbing material on lead leaching and Acinetobacter baumannii, P. aeruginosa, Mycobacterium avium complex and A. polyphaga proliferation. Results:1)Stagnation (<2 hr flow per month) resulted in increased concentrations of waterborne pathogens.2)The hospital building water microbiome was shaped by incoming water quality and building water flow dynamics that arise through usage.3)In both the stainless steel and brass plumbing models, extended stagnation resulted in lead concentrations above drinking water guidelines. Stainless steel materials supported the growth of waterborne pathogens to a greater extent than brass. Conclusion: Improved management of building water can reduce the risk of healthcare association infection.