title: Effect of monochloramine treatment on the microbial ecology of Legionella and associated bacterial populations in a hospital hot water system.
abstract: Opportunistic pathogens, including Legionella spp. and non-tuberculous mycobacteria, can thrive in building hot water systems despite municipal and traditional on-site chlorine disinfection. Monochloramine is a relatively new approach to on-site disinfection, but the microbiological impact of on-site chloramine use has not been well studied. We hypothesized that comparison of the microbial ecology associated with monochloramine treatment versus no on-site treatment would yield highly dissimilar bacterial communities. Hot water samples were collected monthly from 7 locations for three months from two buildings in a Pennsylvania hospital complex supplied with common municipal water: (1) a hospital administrative building (no on-site treatment) and (2) an adjacent acute-care hospital treated on-site with monochloramine to control Legionella spp. Water samples were subjected to DNA extraction, rRNA PCR, and 454 pyrosequencing. Stark differences in the microbiome of the chloraminated water and the control were observed. Bacteria in the treated samples were primarily Sphingomonadales and Limnohabitans, whereas Flexibacter and Planctomycetaceae predominated in untreated control samples. Serendipitously, one sampling month coincided with dysfunction of the on-site disinfection system that resulted in a Legionella bloom detected by sequencing and culture. This study also demonstrates the potential utility of high-throughput DNA sequencing to monitor microbial ecology in water systems.
authors.affiliation: Department of Infectious Diseases and Microbiology, University of Pittsburgh, Graduate School of Public Health, Pittsburgh, PA 15261, USA; Special Pathogens Laboratory, Pittsburgh, PA 15219, USA.
authors.forename: Julianne L
authors.initials: JL
authors.lastname: Baron
authors.affiliation: Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, USA.
authors.forename: J Kirk
authors.initials: JK
authors.lastname: Harris
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA.
authors.forename: Eric P
authors.initials: EP
authors.lastname: Holinger
authors.affiliation: Special Pathogens Laboratory, Pittsburgh, PA 15219, USA.
authors.forename: Scott
authors.initials: S
authors.lastname: Duda
authors.affiliation: Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, USA.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Stevens
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA.
authors.forename: Charles E
authors.initials: CE
authors.lastname: Robertson
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA.
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Ross
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA.
authors.forename: Norman R
authors.initials: NR
authors.lastname: Pace
authors.affiliation: Special Pathogens Laboratory, Pittsburgh, PA 15219, USA; Department of Civil and Environmental Engineering, University of Pittsburgh, Swanson School of Engineering, Pittsburgh, PA 15261, USA. Electronic address: jstout@specialpathogenslab.com.
authors.forename: Janet E
authors.initials: JE
authors.lastname: Stout
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D058448:Biota / Q000187:drug effects*; D002700:Chloramines / Q000494:pharmacology*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D006761:Hospitals; D006358:Hot Temperature; D007875:Legionella / Q000187:drug effects*; D008969:Molecular Sequence Data; D010414:Pennsylvania; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D014871:Water Microbiology
chemical_list: D000890:Anti-Infective Agents; D002700:Chloramines; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; C030816:chloramine
keywords: 454 Pyrosequencing; Bacterial diversity; Ribosomal RNA