Whole-genome sequencing of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae from retail raw milk

The contaminated products of food-producing animals have been proposed to lead the transmission of resistant bacteria to consumers. Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae, which were isolated from raw milk samples, were characterised using whole-genome sequencing in this study. Three confirmed ESBL and one plasmid-mediated AmpC beta-lactamase (pAmpC)-producing isolate were obtained. All of the ESBL-producing isolates showed a multidrug-resistant (MDR) phenotype, but the pAmpC-producing isolate was only resistant to beta-lactams. This study showed that raw milk can contain MDR bacteria that have several resistance determinants and highlighted the necessity of efficiently and routinely screening the products of food-producing animals.