Molecular method for detection of total coliforms in drinking water samples.
This work demonstrates the ability of a bacterial concentration and recovery procedure combined with three different PCR assays targeting the lacZ, wecG, and 16S rRNA genes, respectively, to detect the presence of total coliforms in 100-ml samples of potable water (presence/absence test). PCR assays were first compared to the culture-based Colilert and MI agar methods to determine their ability to detect 147 coliform strains representing 76 species of Enterobacteriaceae encountered in fecal and environmental settings. Results showed that 86 (58.5%) and 109 (74.1%) strains yielded a positive signal with Colilert and MI agar methods, respectively, whereas the lacZ, wecG, and 16S rRNA PCR assays detected 133 (90.5%), 111 (75.5%), and 146 (99.3%) of the 147 total coliform strains tested. These assays were then assessed by testing 122 well water samples collected in the Québec City region of Canada. Results showed that 97 (79.5%) of the samples tested by culture-based methods and 95 (77.9%), 82 (67.2%), and 98 (80.3%) of samples tested using PCR-based methods contained total coliforms, respectively. Consequently, despite the high genetic variability of the total coliform group, this study demonstrated that it is possible to use molecular assays to detect total coliforms in potable water: the 16S rRNA molecular assay was shown to be as efficient as recommended culture-based methods. This assay might be used in combination with an Escherichia coli molecular assay to assess drinking water quality.
Chaire de recherche en eau potable de l'Université Laval, Québec City, Québec, Canada École supérieure d'aménagement du territoire et de développement régional, Université Laval, Québec City, Québec, Canada andree.maheux.3@ulaval.ca.
Andrée F
AF
Maheux
Centre de recherche en infectiologie de l'Université Laval, Axe Maladies infectieuses et immunitaires, Centre de recherche du CHU de Québec, Québec City, Québec, Canada.
Dominique K
DK
Boudreau
Chaire de recherche en eau potable de l'Université Laval, Québec City, Québec, Canada Centre de recherche en aménagement et développement de l'Université Laval, Québec City, Québec, Canada.
Marc-Antoine
MA
Bisson
Chaire de recherche en eau potable de l'Université Laval, Québec City, Québec, Canada Centre de recherche en aménagement et développement de l'Université Laval, Québec City, Québec, Canada.
Vanessa
V
Dion-Dupont
Chaire de recherche en eau potable de l'Université Laval, Québec City, Québec, Canada Centre de recherche en aménagement et développement de l'Université Laval, Québec City, Québec, Canada.
Sébastien
S
Bouchard
Chaire de recherche en eau potable de l'Université Laval, Québec City, Québec, Canada Centre de recherche en aménagement et développement de l'Université Laval, Québec City, Québec, Canada.
Martine
M
Nkuranga
Centre de recherche en infectiologie de l'Université Laval, Axe Maladies infectieuses et immunitaires, Centre de recherche du CHU de Québec, Québec City, Québec, Canada Département de microbiologie-infectiologie et d'immunologie, Faculté de médecine, Université Laval, Québec City, Québec, Canada.
Michel G
MG
Bergeron
Chaire de recherche en eau potable de l'Université Laval, Québec City, Québec, Canada École supérieure d'aménagement du territoire et de développement régional, Université Laval, Québec City, Québec, Canada.
Manuel J
MJ
Rodriguez
D002170:Canada; D015169:Colony Count, Microbial / Q000379:methods*; D004269:DNA, Bacterial / Q000302:isolation & purification; D060766:Drinking Water / Q000382:microbiology*; D004755:Enterobacteriaceae / Q000145:classification / Q000302:isolation & purification*; D004926:Escherichia coli / Q000302:isolation & purification*; D005243:Feces / Q000382:microbiology; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000302:isolation & purification; D014871:Water Microbiology / Q000592:standards*
D004269:DNA, Bacterial; D060766:Drinking Water; D012336:RNA, Ribosomal, 16S