title: Microbial source tracking of private well water samples across at-risk regions in southern Ontario and analysis of traditional fecal indicator bacteria assays including culture and qPCR.
abstract: Many people living in rural areas rely on privately owned wells as their primary source of drinking water. These water sources are at risk for fecal contamination of human, wildlife, and livestock origin. While traditional bacteriological testing involves culture-based methods, microbial source tracking (MST) assays present an opportunity to additionally determine the source of fecal contamination. This study investigated the main host sources of contamination in private well water samples with high levels of Escherichia coli (E. coli), using MST with human and multi-species specific markers. Fecal contamination of human origin was detected in approximately 50% of samples, indicating that current contamination prevention strategies require reconsideration. The relationship between cattle density and fecal contamination of bovine origin was investigated using a Bovine Bacteroidales specific MST assay. Regional variations of microbial sources were examined, and may inform local primary prevention strategies. Additionally, in order to assess MST and E. coli quantitative real time polymerase chain reaction (qPCR) assays as indicators of fecal contamination, these were compared to E. coli culture methods. Variation in results was observed across all assay methods investigated, suggesting the most appropriate routine bacteriological testing methodology cannot be determined without comparison to a method that directly detects the presence of fecal contamination.
authors.affiliation: Public Health Ontario, 181 Barrie Street, P.O. Box 240, Kingston, Ontario K7L 3K2, Canada E-mail: anna.majury@oahpp.ca.
authors.forename: Julia
authors.initials: J
authors.lastname: Krolik
authors.affiliation: Public Health Ontario, 181 Barrie Street, P.O. Box 240, Kingston, Ontario K7L 3K2, Canada E-mail: anna.majury@oahpp.ca.
authors.forename: Allison
authors.initials: A
authors.lastname: Maier
authors.affiliation: Department of Biomedical and Molecular Sciences, Botterell Hall, Queen's University, 18 Stuart Street, Kingston, Ontario K7L 3N6, Canada.
authors.forename: Shawna
authors.initials: S
authors.lastname: Thompson
authors.affiliation: Public Health Ontario, 181 Barrie Street, P.O. Box 240, Kingston, Ontario K7L 3K2, Canada E-mail: anna.majury@oahpp.ca; Department of Biomedical and Molecular Sciences, Botterell Hall, Queen's University, 18 Stuart Street, Kingston, Ontario K7L 3N6, Canada; Department of Public Health Sciences, Carruthers Hall, Queen's University, Kingston, Ontario K7L 2N8, Canada.
authors.forename: Anna
authors.initials: A
authors.lastname: Majury
mesh_terms: D000818:Animals; D000835:Animals, Wild / Q000382:microbiology; D002417:Cattle / Q000382:microbiology; D060766:Drinking Water / Q000382:microbiology*; D004784:Environmental Monitoring; D004926:Escherichia coli / Q000302:isolation & purification*; D005243:Feces / Q000382:microbiology; D060587:Groundwater / Q000382:microbiology*; D006801:Humans; D009864:Ontario; D060888:Real-Time Polymerase Chain Reaction; D060986:Water Wells
chemical_list: D060766:Drinking Water