Detection of extended-spectrum β-lactamases genotype and antibiotic resistance analysis among 30 E. coli isolates from chicken.

Twenty-three extended-spectrum β-lactamases (ESBLs) positive Escherichia coli strains isolated from chicken were analysed for antibiotic resistance. Three different genotypes were detected among these ESBL positive isolates by polymerase chain reaction (PCR): TEM-positive (73.9 %), CTX-M-positive (43.5 %), TEM-and CTX-M-positive (30.4 %), and non-TEM, non-SHV, non-CTX-M ESBL types (13 %). The antibiotic resistance was tested by two-fold dilutions. The results showed that the multi-resistance rate among ESBL-positive strains was higher than that of the ESBL-negative strains, with 95.7 % resistance rates against ampicillin and ceftiofur, and more than 78 % against other third-generation cephalosporins, aminoglycosides, enrofloxacin and trimethoprim-sulfamethoxazple (1/5).