title: Public health implications of Acanthamoeba and multiple potential opportunistic pathogens in roof-harvested rainwater tanks.
abstract: A study of six potential opportunistic pathogens (Acanthamoeba spp., Legionella spp., Legionella longbeachae, Pseudomonas aeruginosa, Mycobacterium avium and Mycobacterium intracellulare) and an accidental human pathogen (Legionella pneumophila) in 134 roof-harvested rainwater (RHRW) tank samples was conducted using quantitative PCR (qPCR). All five opportunistic pathogens and accidental pathogen L. pneumophila were detected in rainwater tanks except Legionella longbeachae. Concentrations ranged up to 3.1×10(6) gene copies per L rainwater for Legionella spp., 9.6×10(5) gene copies per L for P. aeruginosa, 6.8×10(5) gene copies per L for M. intracellulare, 6.6×10(5) gene copies per L for Acanthamoeba spp., 1.1×10(5) gene copies per L for M. avium, and 9.8×10(3) gene copies per L for L. pneumophila. Among the organisms tested, Legionella spp. (99% tanks) were the most prevalent followed by M. intracellulare (78%). A survey of tank-owners provided data on rainwater end-uses. Fecal indicator bacteria (FIB) Escherichia coli and Enterococcus spp. were enumerated using culture-based methods, and assessed for correlations with opportunistic pathogens and L. pneumophila tested in this study. Opportunistic pathogens did not correlate well with FIB except E. coli vs. Legionella spp. (tau=0.151, P=0.009) and E. coli vs. M. intracellulare (tau=0.14, P=0.015). However, M. avium weakly correlated with both L. pneumophila (Kendall's tau=0.017, P=0.006) and M. intracellulare (tau=0.088, P=0.027), and Legionella spp. also weakly correlated with M. intracellulare (tau=0.128, P=0.028). The presence of these potential opportunistic pathogens in tank water may present health risks from both the potable and non-potable uses documented from the current survey data.
authors.affiliation: CSIRO Land and Water, Ecosciences Precinct, 41 Boggo Road, Qld 4102, Australia; Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA.
authors.forename: K A
authors.initials: KA
authors.lastname: Hamilton
authors.affiliation: CSIRO Land and Water, Ecosciences Precinct, 41 Boggo Road, Qld 4102, Australia. Electronic address: Warish.Ahmed@csiro.au.
authors.forename: W
authors.initials: W
authors.lastname: Ahmed
authors.affiliation: CSIRO Land and Water, Ecosciences Precinct, 41 Boggo Road, Qld 4102, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Palmer
authors.affiliation: CSIRO Land and Water, Ecosciences Precinct, 41 Boggo Road, Qld 4102, Australia.
authors.forename: J P S
authors.initials: JPS
authors.lastname: Sidhu
authors.affiliation: CSIRO Land and Water, Ecosciences Precinct, 41 Boggo Road, Qld 4102, Australia.
authors.forename: L
authors.initials: L
authors.lastname: Hodgers
authors.affiliation: CSIRO Land and Water, Ecosciences Precinct, 41 Boggo Road, Qld 4102, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Toze
authors.affiliation: Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA.
authors.forename: C N
authors.initials: CN
authors.lastname: Haas
mesh_terms: D000048:Acanthamoeba / Q000302:isolation & purification*; D001419:Bacteria / Q000302:isolation & purification*; D004269:DNA, Bacterial / Q000032:analysis; D060766:Drinking Water / Q000382:microbiology* / Q000469:parasitology*; D005243:Feces / Q000382:microbiology / Q000469:parasitology; D011793:Queensland; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D011891:Rain / Q000382:microbiology* / Q000469:parasitology*; D060888:Real-Time Polymerase Chain Reaction; D018570:Risk Assessment; D014881:Water Supply
chemical_list: D004269:DNA, Bacterial; D060766:Drinking Water; D012336:RNA, Ribosomal, 16S
keywords: Fecal indicator bacteria; Health risks; Opportunistic pathogens; Quantitative PCR; Rainwater survey; Roof-harvested rainwater