title: Diversity of ribosomal 16S DNA- and RNA-based bacterial community in an office building drinking water system.
abstract: OBJECTIVE
  Next-generation sequencing of 16S ribosomal RNA genes (rDNA) and ribosomal RNA (rRNA) was used to characterize water and biofilm microbiome collected from a drinking water distribution system of an office building after its first year of operation.
  
  
  RESULTS
  The total bacterial community (rDNA) and active bacterial members (rRNA) sequencing databases were generated by Illumina MiSeq PE250 platform. As estimated by Chao1 index, species richness in cold water system was lower (180-260) in biofilms (Sphingomonas spp., Methylobacterium spp., Limnohabitans spp., Rhizobiales order) than in waters (250-580), (also Methylotenera spp.) (P = 0·005, n = 20). Similarly species richness (Chao1) was slightly higher (210-580) in rDNA libraries compared to rRNA libraries (150-400; P = 0·054, n = 24). Active Mycobacterium spp. was found in cross-linked polyethylene (PEX), but not in corresponding copper pipeline biofilm. Nonpathogenic Legionella spp. was found in rDNA libraries but not in rRNA libraries.
  
  
  CONCLUSIONS
  Microbial communities differed between water and biofilms, between cold and hot water systems, locations in the building and between water rRNA and rDNA libraries, as shown by clear clusters in principal component analysis (PcoA). By using the rRNA method, we found that not all bacterial community members were active (e.g. Legionella spp.), whereas other members showed increased activity in some locations; for example, Pseudomonas spp. in hot water circulations' biofilm and order Rhizobiales and Limnohabitans spp. in stagnated locations' water and biofilm.
  
  
  CONCLUSIONS
  rRNA-based methods may be better than rDNA-based methods for evaluating human health implications as rRNA methods can be used to describe the active bacterial fraction. This study indicates that copper as a pipeline material might have an adverse impact on the occurrence of Mycobacterium spp. The activity of Legionella spp. maybe questionable when detected solely by using DNA-based methods.
authors.affiliation: Faculty of Technology, WANDER Nordic Water and Materials Institute, Satakunta University of Applied Sciences, Rauma, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Inkinen
authors.affiliation: Water and Health Unit, National Institute for Health and Welfare (THL), Kuopio, Finland.
authors.forename: B
authors.initials: B
authors.lastname: Jayaprakash
authors.affiliation: U.S. Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, USA.
authors.forename: J W
authors.initials: JW
authors.lastname: Santo Domingo
authors.affiliation: Faculty of Technology, WANDER Nordic Water and Materials Institute, Satakunta University of Applied Sciences, Rauma, Finland.
authors.forename: M M
authors.initials: MM
authors.lastname: Keinänen-Toivola
authors.affiliation: U.S. Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, USA.
authors.forename: H
authors.initials: H
authors.lastname: Ryu
authors.affiliation: Water and Health Unit, National Institute for Health and Welfare (THL), Kuopio, Finland.|U.S. Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, USA.
authors.forename: T
authors.initials: T
authors.lastname: Pitkänen
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D044822:Biodiversity; D004269:DNA, Bacterial / Q000235:genetics; D060766:Drinking Water / Q000382:microbiology*; D059014:High-Throughput Nucleotide Sequencing; D012329:RNA, Bacterial / Q000235:genetics*; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D014871:Water Microbiology
chemical_list: D004269:DNA, Bacterial; D060766:Drinking Water; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S
keywords: biofilms; drinking water; microbial community; next-generation sequencing; pipeline network