Pet treats, Salmonella, and antimicrobial resistance; a One Health problem

Zoonotic pathogens, including Salmonella and antimicrobial resistant bacteria, may contaminate the food or treats consumed by our pets. These may directly impact the health of the pets or may be transferred to humans who are in close contact. To better understand the potential risk, we purchased 505 pet treats from pet and farm supply stores, grocery stores, and online retailers in the U.S. over a period of 16 months to identify and characterize Salmonella and Enterobacterales resistant to Highest Priority Critically Important Antimicrobials. We used selective media to detect Salmonella and bacteria resistant to colistin, carbapenems, fluoroquinolones, and 3rd and 4th generation cephalosporins. Four pig ear treats from Brazil were positive for Salmonella, with serotypes, Muenchen, Derby, Agona and Regent. We found that S. Muenchen and S. Derby were closely related to clinical and environmental isolates from the U.S., Canada, Venezuela, and Colombia. We detected three colistin resistant isolates, Klebsiella pneumoniae, Escherichia coli, and Enterobacter hormaechei, all from pig ear treats from Brazil, harboring the mcr-1.18 resistance gene on identical IncX4 plasmids. In addition, we recovered one carbapenem resistant E. coli harboring both bla_KPC-2 and bla_NDM-5 from a "bully stick". We found that treats originating from North America and treats purchased in grocery stores had a lower risk of contamination with bacteria resistant to the antimicrobials tested. Outreach and extension activities are needed to increase awareness of the risks of contaminated pet treats and to highlight the importance of hand hygiene when feeding and interacting with pets.