Meat from food-producing animals play an important role in the dissemination of antimicrobial resistant bacteria. Active surveillance programs target major agricultural animals but do not include niche food products. In the current investigation, we sought to (1) Identify bacterial pathogens from imported reptile and amphibian meat products and determine the presence of broad spectrum β-lactamase and colistin resistance genes, (2) determine the antimicrobial resistance profiles of Macrococcus caseolyticus isolated from imported meat products and (3) develop a culture medium for the selective isolation of M. caseolyticus. Fifty-three imported reptile and amphibian meat products were purchased from markets in Vancouver, BC and Saskatoon, SK. We found that 41.5% (22/53) of the products carried antimicrobial resistant bacteria with identifiable extended spectrum β-lactamase (ESBL), AmpC β-lactamase, carbapenemase and mobile colistin resistance genes. Seventy-one isolates from 7 genera of Enterobacteriaceae were recovered (from 41 of the 53 products), with none of the Salmonella isolates resistant to any of the antimicrobials tested. One multidrug resistant E. coli, isolated from a soft shell turtle, produced the CTX-M-55 enzyme and possessed the mcr-1 gene conferring mobile colistin resistance. An NDM-1 carbapenemase-producing Acinetobacter spp. was also isolated from a dried turtle carapace. Gram-positive bacteria resembling Staphylococcus aureus were isolated from imported meat samples and identified as Macrococcus caseolyticus; a commensal bacterium found from animal skin and food products. All isolates were resistant to the β-lactam class of drugs, including meropenem, and possessed the mecB gene conferring methicillin resistance. As the ecological distribution of M. caseolyticus in nature is largely unknown, we developed a selective culture medium to help facilitate targeted prevalence studies. Of the prepared selective media challenged, colistin nalidixic acid (CNA) blood agar with ampicillin 0.5µg/ml and meropenem 0.5µg/ml worked the best. This medium facilitated the growth of M. caseolyticus while inhibiting the growth of Gram-negative and most Gram-positive bacteria except for Enterococcus spp. This is the first study to determine the prevalence of antimicrobial resistance and identify ESBL, AmpC β-lactamase, carbapenemase, methicillin and colistin resistance genes from imported reptile and amphibian meat products. More research is required to evaluate the magnitude of the risk that these products have to public health
