Extended-Spectrum Β-Lactamase and Plasmid-Mediated AMPC Genes in Swine and Ground Pork

We investigated the presence of ESBL and AmpC-producing Enterobacteriaceae isolated from 200 rectal swabs of healthy swine and 200 samples of ground pork. Phenotypic testing by using the double synergy differential test (DSDT) for ESBL/AmpC-positive strains was confirmed by PCR and DNA sequence analysis. The localization of beta-lactamase genes was established by conjugation experiments. ESBL and/or AmpC-producing Enterobacteriaceae was found in 52.2% (95/182) of the isolates collected from rectal swabs and 3% (3/100) of isolates obtained from ground pork samples. Polymerase chain reaction and sequencing confirmed the presence of blaTEM-20, blaTEM-34, blaTEM-52, blaCTX-M-1, blaSHV-12, blaTEM-1+SHV-12, blaTEM-20+SHV-12, blaCMY-2, blaTEM-1+ CMY-2, blaACC-1 and blaACC-2. The conjugation assays yielded positive results, denoting a plasmid localization of the genes. Practical Applications In this study, the prevalence of ESBL and AmpC-producing Enterobacteriaceae isolated from rectal swabs of healthy swine and samples of ground pork were determined. ESBL/AmpC-positive strains were confirmed by PCR and DNA sequence analysis. The most frequently isolated species was E.coli, among the most common variants detected TEM-type ESBL, TEM-52 was showed. These findings provide new information about the presence of ESBL/AmpC at the farm level and have important implications for assessments of risks of meat contamination during slaughter.