Point-of-use filters for prevention of health care-acquired Legionnaires' disease: Field evaluation of a new filter product and literature review

Abstract

Background: The Centers for Medicare & Medicaid Services requires that health care facilities assess their building water systems and minimize the risk of growth and spread of Legionella and other waterborne pathogens. Increasingly, point-of-use (POU) filters are being used to prevent exposure to these pathogens. This study provides efficacy and performance specifications (membrane size, pore size, and use restrictions), which will aid in selecting POU filters.

Methods: New faucet and shower filters rated for 62 days of use were evaluated at an acute care facility in Southwestern Ontario, Canada. Five faucets and 5 showers served as controls or were equipped with filters. Hot water samples were collected weekly for 12 weeks and cultured for Legionella, heterotrophic plate count, and Pseudomonas. Literature searches for articles on POU filters used in health care settings were performed using PubMed and Google Scholar. Filter specifications from 5 manufacturers were also compared.

Results: The 62-day POU filters installed on both faucets and showers eliminated Legionella and reduced heterotrophic plate count concentrations for 12 weeks. No Pseudomonas was recovered during this study. Twenty peer-reviewed studies are summarized, and 21 features of 53 POU filters have been compiled.

Conclusions: The information provides infection preventionists and facility engineers with information to verify claims from manufacturers and compare differences among POU products, including validated efficacy, filter design, and operational specifications.

Keywords: Faucet and shower filters; Heterotrophic plate count; Infection control and prevention; Legionella; Mycobacteria; Pseudomonas; Waterborne pathogens.