Characteristics of Extended-Spectrum Cephalosporin-Resistant Escherichia coli Isolated from Swiss and Imported Poultry Meat

摘要

A worrisome phenomenon is the progressive global spread of Enter-obacteriaceae in poultry and chicken meat expressing plasmid-mediated enzymes that inactivate β-lactam antibiotics, suggesting that the food chain might play a role in the epidemiology and the transmission of extended-spectrum cephalosporin-resistant Enterobacteriaceae to humans. The aim of the present study was to further characterize 24 extended-spectrum cephalosporin-resistant Enterobacteriaceae isolated from domestic and imported poultry meat by antibiotic susceptibility testing, identification of the bla_(ESBL)/bla_(pAmpC) genes, conjugation mating experiments and determination of plasmid incompatibility types, multilocus sequence typing, and analysis of the Escherichia coli phylogenetic groups. On account of their resistance patterns, 21 of the total 24 isolates were classified as multidrug resistant. Eleven isolates carried a bla_(CMY-2) gene, whereas 13 isolates harbored a bla_(CTX-M-1) gene. All isolates harbored plasmids that were assigned to 8 of the 18 described plasmid incompatibility groups, the most frequent of which were IncIl, IncFIB, IncB/O, and IncF_(repB). The bla_(ESBL)/bla_(PAmPc) genes were harbored mainly by transferable Incll and IncB/O plasmids. Multilocus sequence typing as well as E. coli phylogenetic group typing revealed a high heterogenicity even among different isolates of the same sample.