Resistance mechanisms and farm-level distribution of fecal Escherichia coli isolates resistant to extended-spectrum cephalosporins in pigs in Spain
Research in Veterinary Science publish this investigation article
February 1st, 2010
INTRODUCTION: Fecal Escherichia coli isolates showing a phenotype of reduced susceptibility or resistance to extended-spectrum cephalosporins are common among pigs in Spain. The aim of this study was to describe the main beta-lactam resistance mechanisms carried by these strains and their distribution at farm-level. MATERIALS AND METHODS: Twenty-nine E. coli isolates showing reduced susceptibility or resistance to extended-spectrum cephalosporins were collected from a sampling frame of 80 pig farms distributed over 13 Spanish provinces. The survey was carried out at the slaughterhouse level in 2004. RESULTS: Of the 29 isolates, 21 (72%) met the criteria for a positive phenotypic confirmatory test for extended-spectrum beta-lactamases (ESBL). The following ESBLs were detected: SHV-12 (12 isolates, 41%), CTX-M-1 (three isolates, 10%), CTX-M-9 (three isolates, 10%), and CTX-M-14 (three isolates, 10%). The remaining eight isolates (28%) were phenotypically non-ESBL, with seven of them (24%) showing mutations on the chromosomal ampC gene promoter at positions -42 (C-->T), -18 (G-->A), -1 (C-->T), and +58 (C-->T). A multiplex PCR for detection of plasmidic class C beta-lactamases was negative for all isolates. CONCLUSION: Different ESBLs and other mechanisms linked to extended-spectrum cephalosporin resistance are widely distributed among fecal E. coli from slaughter pigs in Spain
Escudero E., Vinue L., Teshager T., Torres C. and Moreno MA.
Servicio de Zoonosis de Transmisión Alimentaria y Resistencia a Antimicrobianos (ZTA). Centro de Vigilancia Sanitaria Veterinaria (VISAVET). Universidad Complutense (UCM). | |
Departamento de Sanidad Animal. Facultad de Veterinaria. Universidad Complutense (UCM). | |
Área de Bioquímica y Biología Molecular. Universidad de La Rioja (UR). | |