title: Contamination of Canadian private drinking water sources with antimicrobial resistant Escherichia coli.
abstract: BACKGROUND
  Surface and ground water across the world, including North America, is contaminated with bacteria resistant to antibiotics. The consumption of water contaminated with antimicrobial resistant Escherichia coli (E. coli) has been associated with the carriage of resistant E. coli in people who drink it.
  
  
  OBJECTIVE
  To describe the proportion of drinking water samples submitted from private sources for bacteriological testing that were contaminated with E. coli resistant to antibiotics and to determine risk factors for the contamination of these water sources with resistant and multi-class resistant E. coli.
  
  
  METHODS
  Water samples submitted for bacteriological testing in Ontario and Alberta Canada were tested for E. coli contamination, with a portion of the positive isolates tested for antimicrobial resistance. Households were invited to complete questionnaires to determine putative risk factors for well contamination.
  
  
  RESULTS
  Using multinomial logistic regression, the risk of contamination with E. coli resistant to one or two classes of antibiotics compared to susceptible E. coli was higher for shore wells than drilled wells (odds ratio [OR] 2.8) and higher for farms housing chickens or turkeys (OR 3.0) than properties without poultry. The risk of contamination with multi-class resistant E. coli (3 or more classes) was higher if the properties housed swine (OR 5.5) or cattle (OR 2.2) than properties without these livestock and higher if the wells were located in gravel (OR 2.4) or clay (OR 2.1) than in loam.
  
  
  CONCLUSIONS
  Housing livestock on the property, using a shore well, and having a well located in gravel or clay soil increases the risk of having antimicrobial resistant E. coli in E. coli contaminated wells. To reduce the incidence of water borne disease and the transmission of antimicrobial resistant bacteria, owners of private wells need to take measures to prevent contamination of their drinking water, routinely test their wells for contamination, and use treatments that eliminate bacteria.
authors.affiliation: Mount Sinai Hospital, Toronto, Ontario, Canada. b.coleman@utoronto.ca
authors.forename: Brenda L
authors.initials: BL
authors.lastname: Coleman
authors.forename: Marie
authors.initials: M
authors.lastname: Louie
authors.forename: Marina I
authors.initials: MI
authors.lastname: Salvadori
authors.forename: Scott A
authors.initials: SA
authors.lastname: McEwen
authors.forename: Norman
authors.initials: N
authors.lastname: Neumann
authors.forename: Kristen
authors.initials: K
authors.lastname: Sibley
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Irwin
authors.forename: Frances B
authors.initials: FB
authors.lastname: Jamieson
authors.forename: Danielle
authors.initials: D
authors.lastname: Daignault
authors.forename: Anna
authors.initials: A
authors.lastname: Majury
authors.forename: Shannon
authors.initials: S
authors.lastname: Braithwaite
authors.forename: Bryanne
authors.initials: B
authors.lastname: Crago
authors.forename: Allison J
authors.initials: AJ
authors.lastname: McGeer
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D002170:Canada; D060766:Drinking Water / Q000382:microbiology*; D024881:Drug Resistance, Bacterial / Q000187:drug effects*; D004352:Drug Resistance, Microbial / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects*; D016015:Logistic Models; D012307:Risk Factors; D014871:Water Microbiology; D014876:Water Pollution / Q000032:analysis*; D014881:Water Supply
chemical_list: D000890:Anti-Infective Agents; D060766:Drinking Water