title: Molecular analysis of single room humidifier bacteriology.
abstract: Portable, single-room humidifiers are commonly used in homes for comfort and health benefits, but also create habitats for microbiology. Currently there is no information on home humidifier microbiology aside from anecdotal evidence of infection with opportunistic pathogens and irritation from endotoxin exposure. To obtain a broader perspective on humidifier microbiology, DNAs were isolated from tap source waters, tank waters, and biofilm samples associated with 26 humidifiers of ultrasonic and boiling modes of operation in the Front Range of Colorado. Humidifiers sampled included units operated by individuals in their homes, display models continuously operated by a retail store, and new humidifiers operated in a controlled laboratory study. The V1V2 region of the rRNA gene was amplified and sequenced to determine the taxonomic composition of humidifier samples. Communities encountered were generally low in richness and diversity and were dominated by Sphingomonadales, Rhizobiales, and Burkholderiales of the Proteobacteria, and MLE1-12, a presumably non-photosynthetic representative of the cyanobacterial phylum. Very few sequences of potential health concern were detected. The bacteriology encountered in source waters sampled here was similar to that encountered in previous studies of municipal drinking waters. Source water bacteriology was found to have the greatest effect on tank water and biofilm bacteriology, an effect confirmed by a controlled study comparing ultrasonic and boiler humidifiers fed with tap vs. treated (deionized, reverse osmosis, 0.2 μm filtered) water over a period of two months.
authors.affiliation: Dept. of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA.
authors.forename: Natalie M
authors.initials: NM
authors.lastname: Hull
authors.affiliation: Dept. of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA.
authors.forename: Abigail L
authors.initials: AL
authors.lastname: Reens
authors.affiliation: Dept. of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA.
authors.forename: Charles E
authors.initials: CE
authors.lastname: Robertson
authors.affiliation: Dept. of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA.
authors.forename: Lee F
authors.initials: LF
authors.lastname: Stanish
authors.affiliation: Dept. of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA.
authors.forename: J Kirk
authors.initials: JK
authors.lastname: Harris
authors.affiliation: Dept. of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Stevens
authors.affiliation: Dept. of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA.
authors.forename: Daniel N
authors.initials: DN
authors.lastname: Frank
authors.affiliation: Dept. of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA.
authors.forename: Cassandra
authors.initials: C
authors.lastname: Kotter
authors.affiliation: Dept. of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA. Electronic address: nrpace@colorado.edu.
authors.forename: Norman R
authors.initials: NR
authors.lastname: Pace
mesh_terms: D001419:Bacteria / Q000235:genetics* / Q000302:isolation & purification; D001432:Bacteriology; D044822:Biodiversity; D018441:Biofilms / Q000254:growth & development; D006794:Household Articles / Q000295:instrumentation*; D006813:Humidity; D010802:Phylogeny; D014871:Water Microbiology
keywords: 16S ribosomal RNA sequences; Illumina MiSeq; Microbiology of the built environment; Phylogenetic analysis; Portable humidifiers; V1V2 region