Considering the concept of "One Health," the aim of this study was to determine susceptibility profiles of Escherichia coli in piglets' intestinal microbiota from different farms in Portugal. Beyond antimicrobial susceptibility, the occurrence of multiple antibiotic resistance and detection of phenotypic/genotypic extended-spectrum beta-lactamases (ESBLs) and plasmid mediated AmpC beta-lactamases (pAmpC) were done. From 10 different pig farms, 340 E. coli isolates were obtained from 75 feces samples. Susceptibility to amoxicillin-clavulanic acid (AMC), piperacillin (PIP), cefoxitin (FOX), ceftazidime (CAZ), cefepime (FEP), aztreonam (AZT), imipenem (IP), amikacin (AK), ciprofloxacin (CIP), and trimethoprim-sulfamethoxazole (SXT) was determined. Five-gene panel for amplification of bla genes was used for ESBL (TEM, SHV, CTX-M) and pAmpC (CMY-2, ACC). Among E. coli isolates, 209 were distributed in three resistance profiles: 57.7% MDR, 3.5% extensively drug-resistance (XDR) (resistant to CIP, SXT, and beta-lactams, except IP, with variability to AK) and 0.3% pandrug-resistance (PDR) (resistant to all antibiotics used). pAmpC and/or ESBLs genes were presented in 65% of the isolates. Presence of different associations of bla genes in the same isolate was the most observed (31%), and the most common were an ESBL (TEM) and a pAmpC (CMY-2). Presence of three or four bla genes in various associations were detected. These isolates were very resistant, especially those with four genes, which were resistant to beta-lactams (except IP), CIP, and SXT. This study showed a surprisingly high rate of MDR E. coli isolated in Portuguese piglets, with enzymes that impair activity of the most used antibiotics in human therapeutic.
Keywords: ESBL/pAmpC beta-lactamases; Escherichia coli; high-intensive-production livestock; multidrug-resistance; piglets.