title: Preferential colonization and release of Legionella pneumophila from mature drinking water biofilms grown on copper versus unplasticized polyvinylchloride coupons.
abstract: Legionella occurrence in premise drinking water (DW) systems contributes to legionellosis outbreaks, especially in the presence of suitable protozoan hosts. This study examined L. pneumophila behavior within DW biofilms grown on copper (Cu) and unplasticized polyvinylchloride (uPVC) surfaces in the presence of Acanthamoeba polyphaga. One year-old DW biofilms were established within six CDC biofilm reactors: three each containing Cu or uPVC coupons. Biofilms were then inoculated with L. pneumophila (uPVC-Lp and Cu-Lp), or L. pneumophila and A. polyphaga (uPVC-Lp/Ap and Cu-Lp/Ap) and compared to sterile water inoculated controls (uPVC- and Cu-Control) over a 4 month period. L. pneumophila appeared more persistent by qPCR within Cu biofilms in the presence of A. polyphaga compared to uPVC biofilms with or without A. polyphaga, but maintained their cultivability in uPVC biofilms compared to Cu biofilms. Also, persistent shedding of L. pneumophila cells (assayed by qPCR) in the effluent water implied colonization of L. pneumophila within Cu-coupon reactors compared to no detection from uPVC-coupon reactor effluent 14 days after inoculation. Hence, L. pneumophila appeared to colonize Cu surfaces more effectively and may be shed from the biofilms at a greater frequency and duration compared to L. pneumophila colonized uPVC surfaces with host amoebae playing a role in L. pneumophila persistence within Cu biofilms.
authors.affiliation: Dynamac Corporation c/o US Environmental Protection Agency, Cincinnati, OH, USA. Electronic address: buse.helen@epa.gov.
authors.forename: Helen Y
authors.initials: HY
authors.lastname: Buse
authors.affiliation: National Exposure Research Laboratory, US Environmental Protection Agency, Cincinnati, OH, USA.
authors.forename: Jingrang
authors.initials: J
authors.lastname: Lu
authors.affiliation: Dynamac Corporation c/o US Environmental Protection Agency, Cincinnati, OH, USA.
authors.forename: Ian T
authors.initials: IT
authors.lastname: Struewing
authors.affiliation: National Exposure Research Laboratory, US Environmental Protection Agency, Cincinnati, OH, USA.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Ashbolt
mesh_terms: D000048:Acanthamoeba; D018441:Biofilms; D015169:Colony Count, Microbial; D003300:Copper; D060766:Drinking Water / Q000382:microbiology*; D006801:Humans; D016952:Legionella pneumophila / Q000254:growth & development*; D007876:Legionellosis / Q000382:microbiology*; D011143:Polyvinyl Chloride; D014871:Water Microbiology; D014881:Water Supply
chemical_list: D060766:Drinking Water; D003300:Copper; D011143:Polyvinyl Chloride
keywords: ATP; CDC biofilm reactor; Copper; Drinking water; HPC; uPVC