Antibiotic resistance of Escherichia coli isolated from a poultry slaughterhouse.

The aim of the study was to investigate the antibiotic resistant E. coli strains isolated from bioaerosols and surface swabs in a slaughterhouse as a possible source of poultry meat contamination. The highest air coliforms contamination was during shackling, killing and evisceration of poultry. The strains showed resistance to ampicillin (89%), ceftiofur (62%) and cefquinome (22%), while resistance to ampicillin with sulbactam was only 6%. Resistance to streptomycin and gentamicin was detected in 43% vs. 14% isolates; to tetracycline 33%; to chloramphenicol and florfenicol in 10% vs. 18% isolates; to cotrimoxazol in 35% isolates; to enrofloxacin in 43% isolates. The higher MIC of ceftazidime (3.6 mg x l(-1)) and ceftriaxon (5.2 mg x l(-1)) revealed the presence of ESBLs in 43% of isolates. From 19 selected phenotypically ESBL positive strains, 16 consisted of CMY-2 genes, while CTX-M genes were not detected by PCR. Maldi tof analysis of selected E. coli showed a clear clonal relatedness of environmental strains from various withdrawals.