Systematic Review of Nosocomial Waterborne Infections caused by Nontuberculous Mycobacteria

Background: Healthcare-acquired infections are an increasing priority for health care providers and policy makers. Water is an overlooked source of infectious microorganisms in health care facilities. Waterborne nontuberculous mycobacteria (NTM) are ubiquitous, especially in health care facility water systems, and are known to result in a variety of clinical diseases. Purpose: To contribute to an understanding of prevalence and disease burden, we conducted a systematic review to assess health care associated NTM infections from health care facility water systems. We document susceptible populations, modes of transmission, and the median attack rate. We aim to identify transmission risk factors and inform evidence-based policies for infection control and prevention. Methods: We searched Embase, Pubmed, Web of Science and clinicaltrials.gov without date restrictions. English language articles with original data on NTM waterborne infections in health care settings were included. Study Selection & Data Extraction: Randomized controlled trials, descriptive studies (case reports, case series), case-control studies, cohort studies, cross-sectional surveys, and quasiexperimental studies on nosocomial waterborne infections were included. Three investigators independently screened titles and abstracts for relevant articles, and one screened full-text articles. Data was extracted by one investigator, and a second confirmed accuracy for 10% of results. Results: We included 22 observational studies. Immunocompromised, post-surgical, and hemodialysis patients were commonly affected populations, and a range of exposure routes such as uncovered central venous catheters (CVCs), wound exposure, and contamination during surgical procedures was reported. The median attack rate was 12.1% (interquartile range, 11- 27.2). Conclusion: Waterborne NTM infection affects susceptible patients through common, preventable exposure routes. Effective prevention strategies will require both medical and environmental health expertise, and inter-professional cooperation will optimize these efforts. Additional high-quality studies using genotypic methods are also needed, especially in low- and middle-income countries.