Occurrence of extended-spectrum β-lactamase and AmpC-producing Escherichia coli in retail meat products from the Maritime Provinces, Canada

This study was conducted to determine the occurrence of antimicrobial resistance to the extended-spectrum cephalosporins (ESC) in Escherichia coli isolates. The isolates were collected from retail meat products collected in the Maritime Provinces of Canada. Our analyses involved the use of both selective and traditional culture methods; we also conducted genotype analyses using multiplex polymerase chain reactions. ESC-resistant (ESC-R) E. coli were detected in 33 of 559 samples (5.9%) using the traditional culture method, compared with 151 of 557 samples (27.1%) using the selective culture method. We recovered more isolates of ESC-R E. coli from poultry compared with beef and pork (P < 0.001). Multidrug resistance, extended-spectrum beta-lactamase (ESBL), and AmpC phenotypes were more common in chicken-derived isolates than other retail meat products (P < 0.001). From the 98 isolates examined, 76 isolates (77.6%) were positive for either ESBL and AmpC beta-lactamases or both. Among the 76 isolates, bla(CMY-2) (78.9%), bla(CTXM) (46.1%), bla(TEM) ( 21.1%), and bla(SHV) (1.3%) genes were detected. Among the bla(CTXM)-producing isolates, bla(CTXM-1), bla(CTXM-2), and bla(CTXM-9) phylogenetic groups were detected. b-lactamase genes were more commonly detected in chicken-derived isolates compared with other meat types (P < 0.01). This study demonstrates the occurrence of ESBL-and AmpC-resistance genes in retail meat products in the Maritime Provinces of Canada. We found that selective culture significantly improved the recovery of ESC-R E. coli isolates from retail meat samples.

Automated summary

This study aimed to determine the occurrence of antimicrobial resistance to the extended-spectrum cephalosporins in Escherichia coli isolates from retail meat products in the Maritime Provinces of Canada. It was found that selective culture significantly improved the recovery of ESC-resistant E. coli isolates from retail meat samples. The study demonstrated the presence of ESBL-and AmpC-resistance genes in retail meat products in the Maritime Provinces of Canada.