High prevalence of extended-spectrum β-lactamase, plasmid-mediated AmpC, and carbapenemase genes in pet food.

We evaluated the pet food contained in 30 packages as a potential origin of extended-spectrum cephalosporin-resistant Gram-negative organisms and β-lactamase genes (bla). Live bacteria were not detected by selective culture. However, PCR investigations on food DNA extracts indicated that samples harbored the blaCTX-M-15 (53.3%), blaCMY-4 (20%), and blaVEB-4-like (6.7%) genes. Particularly worrisome was the presence of blaOXA-48-like carbapenemases (13.3%). The original pet food ingredients and/or the production processes were highly contaminated with bacteria carrying clinically relevant acquired bla genes.