Antimicrobial resistant bacteria from imported vegetables and spices purchased from niche markets in Saskatoon, Saskatchewan
Date
2019-02-04
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0000-0003-4932-4981
Type
Thesis
Degree Level
Masters
Abstract
The role of imported vegetables and spices in the epidemiology of antimicrobial resistance in Canada has been inadequately studied. In this investigation, resistant organisms from imported vegetables and spices in Saskatoon, Saskatchewan were investigated.
A total of 147 vegetable and spice products imported from primarily Asian and African countries, were purchased from international markets in Saskatoon, Saskatchewan. Samples were selectively cultured for a panel of bacteria where resistance is known to be emerging. The proportion of samples positive for each organism were as follows: E. coli (n=15, 10.2%), Salmonella spp. (n=2, 1.4%), Enterobacter spp. (n=12, 8.2%), K. pneumoniae (n=2, 1.4%), Acinetobacter spp. (n=12, 8.2%), Pseudomonas spp. (n=10, 6.8%), S. aureus (n=7, 4.8%) and Enterococcus spp. (n=69, 46.9%). Antimicrobial susceptibility testing of isolates was conducted by broth micro dilution and agar dilution. Based on the susceptibility of each organism, isolates were then screened for resistance genes (β-lactamases and plasmid mediated quinolones resistance determinants) by PCR.
Multidrug resistant Enterobacteriaceae were identified. Among other organisms, methicillin resistant S. aureus (MRSA) were identified. Resistance to the penicillins, cephalosporins, quinolones and aminoglycosides mediated by broad spectrum β-lactamases and plasmid mediated quinolone resistance determinants (PMQR) were identified. Broad spectrum β-lactamase producers were cultured from 6/147 (4.1%) of samples tested. The most common enzymes found were CTX-M-15 (n=4), TEM-4 (n=1) and SHV-142 (n=1). The PMQRs (QnrB1, QnrB2, QnrS1 and AAC(6’)-Ib-cr) containing isolates were cultured from 2/147 (1.4%) of the samples. While all multi-drug resistant Enterobacteriaceae isolates were susceptible to meropenem and colistin, several non-fermenters were resistant to these drugs. However, none of these organisms produced carbapenemases or possessed mobilized colistin resistance determinants (MCR-1, MCR-2, MCR-3, MCR-4). Salmonella spp. were susceptible to the most of tested drugs. With the exception of two MRSA, the S. aureus isolates were susceptible to other non-beta lactam drugs. Enterococcus spp. isolates were resistant to various drugs but susceptible to ampicillin, penicillin and vancomycin.
It was interesting to observe that all of the multi-drug resistant organisms originated from countries which are recognized to have a high prevalence of resistance. Therefore, further study is required to understand the extent of antimicrobial resistance transmission by imported vegetables and spices from these countries to Canada.
Description
Keywords
Antimicrobial resistance, Imported foods
Citation
Degree
Master of Science (M.Sc.)
Department
Veterinary Microbiology
Program
Veterinary Microbiology