title: Detection of Legionella, L. pneumophila and Mycobacterium avium complex (MAC) along potable water distribution pipelines.
abstract: Inhalation of potable water presents a potential route of exposure to opportunistic pathogens and hence warrants significant public health concern. This study used qPCR to detect opportunistic pathogens Legionella spp., L. pneumophila and MAC at multiple points along two potable water distribution pipelines. One used chlorine disinfection and the other chloramine disinfection. Samples were collected four times over the year to provide seasonal variation and the chlorine or chloramine residual was measured during collection. Legionella spp., L. pneumophila and MAC were detected in both distribution systems throughout the year and were all detected at a maximum concentration of 103 copies/mL in the chlorine disinfected system and 106, 103 and 104 copies/mL respectively in the chloramine disinfected system. The concentrations of these opportunistic pathogens were primarily controlled throughout the distribution network through the maintenance of disinfection residuals. At a dead-end and when the disinfection residual was not maintained significant (p < 0.05) increases in concentration were observed when compared to the concentration measured closest to the processing plant in the same pipeline and sampling period. Total coliforms were not present in any water sample collected. This study demonstrates the ability of Legionella spp., L. pneumophila and MAC to survive the potable water disinfection process and highlights the need for greater measures to control these organisms along the distribution pipeline and at point of use.
authors.affiliation: Health and the Environment, Flinders University, GPO Box 2100, Adelaide 5001, Australia. Harriet.Whiley@flinders.edu.au.
authors.forename: Harriet
authors.initials: H
authors.lastname: Whiley
authors.affiliation: South Australian Water Corporation, 250 Victoria square, Adelaide 5000, Australia. Alex.Keegan@sawater.com.au.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Keegan
authors.affiliation: Health and the Environment, Flinders University, GPO Box 2100, Adelaide 5001, Australia. Howard.Fallowfield@flinders.edu.au.
authors.forename: Howard
authors.initials: H
authors.lastname: Fallowfield
authors.affiliation: Health and the Environment, Flinders University, GPO Box 2100, Adelaide 5001, Australia. Richard.Bentham@flinders.edu.au.
authors.forename: Richard
authors.initials: R
authors.lastname: Bentham
mesh_terms: D002700:Chloramines; D002713:Chlorine; D004269:DNA, Bacterial / Q000032:analysis; D004203:Disinfection; D060766:Drinking Water / Q000382:microbiology*; D007875:Legionella / Q000235:genetics / Q000302:isolation & purification*; D015269:Mycobacterium avium Complex / Q000235:genetics / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction; D014871:Water Microbiology; D014881:Water Supply
chemical_list: D002700:Chloramines; D004269:DNA, Bacterial; D060766:Drinking Water; D002713:Chlorine; C030816:chloramine