Prevalence of extended-spectrum β-lactamase-producing Enterobacteriaceae in meat products sold in Navarra, Spain

Patterns of resistance in β-lactamase-producing Enterobacteriaceae family were investigated in isolates from 141 meat products (beef, poultry and pork) purchased in Spain. The strains that grow in ChromID ESBL agar plates were confirmed using the paired disk diffusion method. Resistance to amoxicillin/clavulanic acid, ceftazidime, ceftriaxone, aztreonam, cefpodoxime, gentamicin, doxycycline, cotrimoxazol, norfloxacin, piperacillin/tazobactam, fosfomycin and cefoxitin were tested following CLSI recommendations. Minimum inhibitory concentrations were determined by the MicroScan® NM37 panel and β-lactamase genes were detected using multiplex PCR and sequencing. Results show poultry as the meat product having the highest prevalence (84%), with Escherichia coli being the predominant bacteria (71.3%). Predominant β-lactamase types were CTX-M (37.8%), followed by CTX-M + TEM combination (20.7%), TEM (17%), SHV (12.2%), TEM + SHV combination (10.9%) and OXA (1.2%). 93.9% of the strains were resistant to one or more β-lactam antibiotics. Results indicate a widespread distribution of ESBL-producing Enterobacteriaceae in meat products, with a high rate of β-lactam resistance and a low rate of AmpC cephalosporinase-producing strains.