Background: Legionella pneumophila, Mycobacterium avium , and Pseudomonas aeruginosa are opportunistic premise plumbing pathogens (OPPPs) that persist and grow in household plumbing, habitats they share with humans. Infections caused by these OPPPs involve individuals with preexisting risk factors and frequently require hospitalization.

Objectives: The objectives of this report are to alert professionals of the impact of OPPPs, the fact that 30% of the population may be exposed to OPPPs, and the need to develop means to reduce OPPP exposure. We herein present a review of the epidemiology and ecology of these three bacterial OPPPs, specifically to identify common and unique features.

Methods: A Water Research Foundation–sponsored workshop gathered experts from across the United States to review the characteristics of OPPPs, identify problems, and develop a list of research priorities to address critical knowledge gaps with respect to increasing OPPP-associated disease.

Discussion: OPPPs share the common characteristics of disinfectant resistance and growth in biofilms in water distribution systems or premise plumbing. Thus, they share a number of habitats with humans (e.g., showers) that can lead to exposure and infection. The frequency of OPPP-infected individuals is rising and will likely continue to rise as the number of at-risk individuals is increasing. Improved reporting of OPPP disease and increased understanding of the genetic, physiologic, and structural characteristics governing the persistence and growth of OPPPs in drinking water distribution systems and premise plumbing is needed.

Conclusions: Because broadly effective community-level engineering interventions for the control of OPPPs have yet to be identified, and because the number of at-risk individuals will continue to rise, it is likely that OPPP-related infections will continue to increase. However, it is possible that individuals can take measures (e.g., raise hot water heater temperatures and filter water) to reduce home exposures.

Citation: Falkinham JO III, Hilborn ED, Arduino MJ, Pruden A, Edwards MA. 2015. Epidemiology and ecology of opportunistic premise plumbing pathogens: Legionella pneumophila , Mycobacterium avium , and Pseudomonas aeruginosa . Environ Health Perspect 123:749–758; http://dx.doi.org/10.1289/ehp.1408692

Address correspondence to J.O. Falkinham III, Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061-0406 USA. Telephone: (540) 231-5931. E-mail: jofiii@vt.edu

A multidisciplinary workshop expert panel authored this review based on the proceedings of the workshop “Research Needs for Opportunistic Pathogens in Premise Plumbing.” The workshop was organized and co-chaired by A.P, M.A.E., and J.O.F. III and sponsored by a grant from the Water Research Foundation (Project 4379).

The views expressed in this report are those of the individual authors and do not necessarily reflect the views and policies of the U.S. Environmental Protection Agency (E.D.H.) or the Centers for Disease Control and Prevention/Agency for Toxic Substances and Disease Registry (M.J.A.). Mention of trade names or commercial products does not constitute endorsement or recommendation for use.

The authors declare they have no actual or potential competing financial interests.

Received: 14 May 2014 Accepted: 17 March 2015 Advance Publication: 20 March 2015 Final Publication: 1 August 2015

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