PREVALENCE AND CHARACTERISTICS OF ESCHERICHIA COLI AND SALMONELLA SPP. IN THE FECES OF WILD URBAN NORWAY AND BLACK RATS (RATTUS NORVEGICUS AND RATTUS RATTUS) FROM AN INNER-CITY NEIGHBORHOOD OF VANCOUVER, CANADA.
Although rat feces are widely suspected to be a source of pathogenic bacteria, few investigators have studied fecal pathogens in rats. We investigated the prevalence and characteristics of Escherichia coli and Salmonella spp. in Norway and black rats (Rattus norvegicus and Rattus rattus, respectively) from an urban neighborhood of Vancouver, Canada, collected September 2011-August 2012. Colon content was cultured for E. coli and Salmonella spp. and screened for the seven most-common enteropathogenic Shiga toxin-producing E. coli (STEC) serotypes by PCR. Isolates were tested for antimicrobial resistance and Salmonella isolates were serotyped. We detected E. coli in 397/633 (62.7%) urban rats. Forty-one of 397 (6.5%) E. coli isolates were resistant to ≥ 1 antimicrobial while 17 (4.3%) were multidrug resistant (including two isolates demonstrating extended-spectrum β-lactamase resistance). Ten of 633 (1.6%) urban rats were carrying STEC serotypes including O145, O103, O26, and O45. Norway rats were more likely to be carrying E. coli compared to black rats, and there was geographic clustering of specific resistance patterns and STEC serotypes. Salmonella spp. were detected in 3/633 (0.5%) rats including serotypes Derby, Indiana, and Enteritidis. In contrast to zoonotic pathogens for which rats are the natural reservoir (e.g., Leptospira interrogans, Rickettsia typhi, Seoul virus), rats likely acquired E. coli and Salmonella spp. from their environment. The ability of rats to be a 'sponge' for environmental pathogens has received little consideration, and the ecology and public health significance of these organisms in rats requires further investigation.
1  School of Population and Public Health, University of British Columbia, 2206 E Mall, Vancouver, British Columbia V6T 1Z9, Canada.|2  Animal Health Centre, British Columbia Ministry of Agriculture, 1767 Angus Campbell Road, Abbotsford, British Columbia V3G 2M3, Canada.
Chelsea G
CG
Himsworth
2  Animal Health Centre, British Columbia Ministry of Agriculture, 1767 Angus Campbell Road, Abbotsford, British Columbia V3G 2M3, Canada.
Erin
E
Zabek
3  Laboratory for Foodborne Zoonoses, Public Health Agency of Canada, 160 Research Lane, Guelph, Ontario N1G 5B2, Canada.
Andrea
A
Desruisseau
3  Laboratory for Foodborne Zoonoses, Public Health Agency of Canada, 160 Research Lane, Guelph, Ontario N1G 5B2, Canada.
E Jane
EJ
Parmley
3  Laboratory for Foodborne Zoonoses, Public Health Agency of Canada, 160 Research Lane, Guelph, Ontario N1G 5B2, Canada.
Richard
R
Reid-Smith
4  Department of Pathobiology and Canadian Wildlife Health Cooperative, University of Guelph, 50 Stone Road, Guelph, Ontario N1G 2W1, Canada.
Claire M
CM
Jardine
5  British Columbia Centre for Disease Control, 655 W 12th Avenue, Vancouver, British Columbia V5Z 4R4, Canada.|6  Department of Pathology and Laboratory Medicine, University of British Columbia, 2211 Westbrook Mall, Vancouver, British Columbia V6T 2B5, Canada.
Patrick
P
Tang
1  School of Population and Public Health, University of British Columbia, 2206 E Mall, Vancouver, British Columbia V6T 1Z9, Canada.
David M
DM
Patrick
D000818:Animals; D000835:Animals, Wild / Q000382:microbiology; D001955:British Columbia / Q000453:epidemiology; D002947:Cities / Q000453:epidemiology; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000662:veterinary*; D005243:Feces / Q000382:microbiology; D005260:Female; D008297:Male; D015995:Prevalence; D051381:Rats / Q000382:microbiology*; D012475:Salmonella / Q000187:drug effects; D012481:Salmonella Infections, Animal / Q000453:epidemiology*; D054323:Shiga-Toxigenic Escherichia coli / Q000187:drug effects
Antimicrobial resistance; Escherichia coli; Rattus norvegicus; Rattus rattus; Salmonella spp.; enteropathogenic; urban