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Antimicrobial susceptibility of Escherichia coli strains isolated from food-producing, companion and wild animals, in Portugal – Characterization of isolates with reduced susceptibility to third generation cephalosporins and cephamycins
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Abstract(s)
Escherichia coli is a common inhabitant of the gastrointestinal tract of humans and animals, but is also a causative agent of diarrhea and extraintestinal infections. There is ongoing concern about the risks posed to human health by antimicrobial resistant bacteria isolated from animals.
This study was conducted on 602 Escherichia coli isolates recovered from food-producing (n=217), companion (n=114) and wild animals (n=271), over the period of 2009-2013, to determine their antimicrobial susceptibility to a panel of ten antimicrobials (ampicillin, cefotaxime, ciprofloxacin, nalidixic acid, trimethoprim, sulfamethoxazole, chloramphenicol, streptomycine, gentamicine and tetracycline), through the determination of Minimum Inhibitory Concentration (MIC), using the agar dilution technique. Susceptibility to cefoxitin was determined through disk diffusion method.
Molecular characterization of isolates showing a non-wild type MIC to cefotaxime was performed, to determine extended spectrum β-lactamases (ESBL), plasmid mediated AmpC (PMAβ), plasmid mediated quinolone (PMQR) resistance determinants and mobile genetic elements involved in the dissemination of resistance genes.
Overall, isolates recovered from food producing animals showed higher frequencies of resistance towards all antimicrobials tested and multidrug resistance (MDR) (53%), followed by companion (43%) and wild animals (30%).
Fifty isolates presented a non-wild phenotype to cefotaxime and resistance or intermediate susceptibility to cefoxitin, being 14 (12.3%) from pets, 19 (8.8%) from food producing animals and 17 (6.3%) from wild animals. Polymerase chain reaction and sequencing of the amplicons confirmed the presence of blaCTX-M-type (n=14), blaSHV-type (n=2), blaTEM-type (n=31), blaOXA-type (n=6) and plasmid-mediated AmpC β-lactamases (PMAβ) genes (n=8). Plasmid-mediated quinolone resistance-encoding genes were detected in ten isolates: aac(6')-Ib-cr (n=6) qnrB17 (n=1), qnrS1(n=1) and qnrB19 (n=2). Twenty five isolates carried class 1 integrons and two carried class 2 integrons.
This study agrees that animals may act as important reservoirs of E. coli isolates carrying ESBL and PMAβ-encoding genes, which might be transmissible to humans through direct contact or the food chain and, a potential source for human pathogens to acquire these resistance genes.
Description
Keywords
Resistência aos Antibióticos Escherichia coli Food-producing Animals Companion Animals Wild Animals
Pedagogical Context
Citation
Clemente L., Manageiro V., Jones-Dias D., Ferreira E., Correia I., Albuquerque T., Geraldes M., Matos F., Almendra C., Themudo P., Caniça M. 2014. Antimicrobial susceptibility of Escherichia coli strains isolated from food-producing, companion and wild animals, in Portugal – Characterization of isolates with reduced susceptibility to third generation cephalosporins and cephamycins. Congresso Ciências Veterinárias 2014: Ciências Veterinárias - Praxis e Futuro. Instituto Nacional de Investigação Agrária e Veterinária, Oeiras, Portugal.