title: Shift in the microbial ecology of a hospital hot water system following the introduction of an on-site monochloramine disinfection system.
abstract: Drinking water distribution systems, including premise plumbing, contain a diverse microbiological community that may include opportunistic pathogens. On-site supplemental disinfection systems have been proposed as a control method for opportunistic pathogens in premise plumbing. The majority of on-site disinfection systems to date have been installed in hospitals due to the high concentration of opportunistic pathogen susceptible occupants. The installation of on-site supplemental disinfection systems in hospitals allows for evaluation of the impact of on-site disinfection systems on drinking water system microbial ecology prior to widespread application. This study evaluated the impact of supplemental monochloramine on the microbial ecology of a hospital's hot water system. Samples were taken three months and immediately prior to monochloramine treatment and monthly for the first six months of treatment, and all samples were subjected to high throughput Illumina 16S rRNA region sequencing. The microbial community composition of monochloramine treated samples was dramatically different than the baseline months. There was an immediate shift towards decreased relative abundance of Betaproteobacteria, and increased relative abundance of Firmicutes, Alphaproteobacteria, Gammaproteobacteria, Cyanobacteria and Actinobacteria. Following treatment, microbial populations grouped by sampling location rather than sampling time. Over the course of treatment the relative abundance of certain genera containing opportunistic pathogens and genera containing denitrifying bacteria increased. The results demonstrate the driving influence of supplemental disinfection on premise plumbing microbial ecology and suggest the value of further investigation into the overall effects of premise plumbing disinfection strategies on microbial ecology and not solely specific target microorganisms.
authors.affiliation: Department of Infectious Diseases and Microbiology, University of Pittsburgh, Graduate School of Public Health, Pittsburgh, Pennsylvania, United States of America; Special Pathogens Laboratory, Pittsburgh, Pennsylvania, United States of America.
authors.forename: Julianne L
authors.initials: JL
authors.lastname: Baron
authors.affiliation: Department of Civil and Environmental Engineering, University of Pittsburgh, Swanson School of Engineering, Pittsburgh, Pennsylvania, United States of America.
authors.forename: Amit
authors.initials: A
authors.lastname: Vikram
authors.affiliation: Special Pathogens Laboratory, Pittsburgh, Pennsylvania, United States of America.
authors.forename: Scott
authors.initials: S
authors.lastname: Duda
authors.affiliation: Special Pathogens Laboratory, Pittsburgh, Pennsylvania, United States of America; Department of Civil and Environmental Engineering, University of Pittsburgh, Swanson School of Engineering, Pittsburgh, Pennsylvania, United States of America.
authors.forename: Janet E
authors.initials: JE
authors.lastname: Stout
authors.affiliation: Department of Civil and Environmental Engineering, University of Pittsburgh, Swanson School of Engineering, Pittsburgh, Pennsylvania, United States of America; Department of Computational and Systems Biology, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania, United States of America.
authors.forename: Kyle
authors.initials: K
authors.lastname: Bibby
mesh_terms: D039903:Actinobacteria / Q000235:genetics / Q000254:growth & development; D001483:Base Sequence; D018441:Biofilms / Q000187:drug effects / Q000254:growth & development; D002700:Chloramines / Q000494:pharmacology*; D000458:Cyanobacteria / Q000235:genetics / Q000254:growth & development; D004269:DNA, Bacterial / Q000235:genetics; D004202:Disinfectants / Q000494:pharmacology; D004203:Disinfection / Q000379:methods*; D060766:Drinking Water / Q000382:microbiology*; D006750:Hospital Distribution Systems; D020560:Proteobacteria / Q000235:genetics / Q000254:growth & development; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012498:Sanitary Engineering; D017422:Sequence Analysis, DNA; D062606:Tertiary Care Centers; D014871:Water Microbiology; D018508:Water Purification / Q000379:methods*; D060753:Water Quality
chemical_list: D002700:Chloramines; D004269:DNA, Bacterial; D004202:Disinfectants; D060766:Drinking Water; D012336:RNA, Ribosomal, 16S; C030816:chloramine