The role of drinking water as a source of transmission of ...

The role of drinking water as a source of transmission of antimicrobial resistant Escherichia coli Brenda L. Coleman, Allison McGeer, Marina Salvadori, Ian Johnson, Iris Gutmanis, Sue Bondy, Norm Neuman, Marie Louis, Scott McEwen, Fran Jamieson, & Rebecca Irwin Antimicrobial Resistance What is it? Why do we care? How does it occur? Selective pressure Transmission Escherichia coli Human colonization

Human infection Water as a vehicle for transmission E. coli indicator of contamination Private drinking water 10-50% of Canadian households 30-50% test water 2-20% contaminated with E. coli Objectives 1. Measure the proportion of E. coli positive water samples that are antimicrobial resistant (AR) 2. Measure the prevalence of human carriage of AR E. coli 3. Determine whether the use of water contaminated with AR E. coli is associated with human carriage

Sampling Public health labs (Water samples) Standard testing for bacterial contamination at participating laboratories E. coli - positive No bacterial contamination Surveillance (Water samples) E. coli susceptibility tested sample Resistant

Case-control (Households) Eligible & non-replicate households Household questionnaire Case Cross-sectional (Individuals) Susceptible Control A

Control B Eligible individuals Personal questionnaire & rectal swab Resistant Susceptible Water samples 340,009 tested 15,238 E. coli (4.5%) 6,492 susceptibility tested 645 resistant (9.9%)

Proportion of E. coli positive w ater sam ples that w ere antim icrobial resistant Ontario May 2005-Septem ber 2006 12% 10% 6% 4% One or more Sulphonamide Aminoglycoside Fluoroquinolone

Beta lactam Tetracycline Chloramphenicol 0% MDR 2% Cephalothin % E. coli +ve 8%

Proportion of E. coli- positive w ater sam ples and proportion of antim icrobial resistant E. coli- positive isolates Ontario, May 1, 2005 - Septem ber 30, 2006 25% E. coli Resistant 15% 10% Peterborough Kingston Orillia Toronto

Ottawa London 0% ONTARIO 5% Hamilton Per 100 submitted samples 20% Human samples

1,710 households eligible 831 household questionnaires 655 households 985 personal questionnaires 488 households 699 rectal swabs Households & Subjects 488 households 108 with AR E. coli water source

69 with untreated AR E. coli 699 subjects 12 to 87 years old Males = females 433 (62%) used tap water only 376 (54%) travelled outside Canada 185 (27%) had direct livestock contact 85 (12%) used antibiotic Chloramphenicol Tetracycline Sulphonamide Fluoroquinolone Aminoglycoside

Ampicillin Multi-drug One or more Proportion of rectal swabs with AR E. coli Ontario, 2005-2007 50% 40% 30% 20%

10% 0% Theorized relationship between human carriage & consumption of antimicrobial resistant E. coli Potential effect modifier: Bottled water Primary predictor: Water used Outcome: Carriage of antimicrobial resistant E. coli Potential confounders:

Age Antibiotic use Sex Hospitalization Household education Child in day care Household income Household size Laboratory region Contact with livestock Mode of data collection Farming property Days between water sample Contact with dog/cat & interview Contact with raw meat Travel Final multivariable model Predictor

RR 95% Conf. interval Water used (contaminated & not treated) 1.4 1.1, 1.7 Travel outside Canada 1.3 1.1, 1.6 Contact with cattle

1.3 1.0, 1.5 Sex (male) 1.2 1.0, 1.5 Limitations Convenience sample Age of subjects

Lack of exposure dose/treatment of water Causation Conclusions Private drinking water sources are contaminated with AR E. coli Relatively high prevalence of AR E. coli carriage in non-institutionalized residents Carriage of AR E. coli is associated with the use of contaminated water