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Occurrence of Opportunistic Pathogens Legionella pneumophila and non-tuberculous mycobacteria in hospital plumbing systems
Citation:
Hoelle, J., M. Coughlin, E. Sotkiewicz, J. Lu, S. Pfaller, M. Rodgers, AND H. Ryu. Occurrence of Opportunistic Pathogens Legionella pneumophila and non-tuberculous mycobacteria in hospital plumbing systems. Presented at ASM General Meeting, Boston, MA, June 16 - 20, 2016.
Impact/Purpose:
Abstract submission for the ASM General Meeting held in Boston June 16-20, 2016.
Description:
Occurrence of Opportunistic Pathogens Legionella pneumophila and non-tuberculous mycobacteria in hospital plumbing systems Jill Hoelle, Michael Coughlin, Elizabeth Sotkiewicz, Jingrang Lu, Stacy Pfaller, Mark Rodgers, and Hodon Ryu U.S. Environmental Protection Agency, Cincinnati, OHWeas Engineering, Westfield, INOpportunistic premise plumbing pathogens (OPPPs) such as Legionella pneumophila, Mycobacterium avium, and Pseudomonas aeruginosa have been detected in premise plumbing systems, possibly due to disinfectant resistance and/or thermotolerance. Moreover, their ability to form biofilm and to grow in phagocytic amoeba could provide insulation from high concentrations of disinfectants. Copper-silver (Cu-Ag) ionization has been used in hospital water systems as an additional treatment barrier, consequently reducing disinfection by-products. In this study, we investigated the occurrence of three OPPPs and phagocytic amoeba and the efficacy of Cu-Ag ionization in hospital plumbing systems under varying levels of chlorine residuals and water temperature. A total of 197 water and 31 swab samples were collected from 14 medical facilities including two buildings that used Cu-Ag ionization. The samples were analyzed for OPPPs and phagocytic amoeba using qPCR assays for L. pneumophila, nontuberculous mycobacteria (NTM) (i.e., M. avium and M. intracellulare), Pseudomonas aeruginosa and two amoeba (i.e., Acanthamoeba and Vermamoeba vermiformis). Legionella was cultured and serotyping was performed using a latex agglutination test and multi-gene analysis of four virulence factors. Of 166 water samples from facilities without Cu-Ag ionization, Legionella spp. were the most prevalent (44%, 73/166), followed by Vermamoeba (13%), NTM (11%), and Pseudomonas aeruginosa (6%). Of Legionella positive samples, 35 and 25 water samples were confirmed as L. pneumophila serotype 1 by latex agglutination test and the multi-gene analysis, respectively. Overall, OPPPs were more prevalent in warm taps with low chlorine residuals than in cold water with higher chlorine residuals. In the facilities using Cu-Ag ionization, the prevalence of Legionella in the water was low (3%, 1/31), whereas Mycobacterium avium was detected at a high frequency (61%, 19/31). In addition to water, six of 26 swab samples were positive for L. pneumophila including four serotype 1 positives, whereas M. avium was detected in one of five swabs from Cu-Ag ionization facilities. The other target microorganisms were not detected in any swab samples. The opposing treatability trend of L. pneumophila and NTM by Cu-Ag ionization is a significant finding in terms of a quasi-dominance of M. avium in premise plumbing systems, which would lead to further studies for additional and/or new treatment technologies.
