Surveillance study of faecal E. coli isolates producing AmpC and extended spectrum β-lactamases (ESBLs) enzymes in poultry and workers from aviculture around Tehran

BACKGROUND: AmpC and ESBLs as mediated-plasmid extended spectrum β-lactabases are the main factors of resistance to extended-spectrum cephalosporins in enterobacteriacea especially E. coli and will follow treatment failure, high costs of treatment in human and economic losses in the poultry industry. OBJECTIVES: The purpose of this study was to screen and study the faecal E. coli isolates producing extended spectrum β-lactamases (ESBLs) and AmpC enzymes and related workers. METHODS: A total of 500 cloacal swab samples from broiler chickens and 25 rectal swab samples from workers were collected from five poultry houses around Tehran. All samples were seeded on MacConkey agar and identification of E. coli isolates were performed via biochemical tests. Antibiotic susceptibility was determined against 12 antibiotics using the disk diffusion method as recommended by the clinical and laboratory standard institute (CLSI2012). Ceftazidim / ceftazidim-clavolanic acid and cefoxitin / cefoxitin-EDTA disks were used for the detection of ESBL and AmpC phenotypes, respectively. phonetic analysis of the drug resistances was performed via SPSS software and Chi-square test. ESBL- producing E. coli screened by PCR for the presence of genes encoding beta-lactamases of TEM, CTX-M and SHV.       RESULTS: A total 467 E. coli isolates were isolated from 88.9% of the samples as 92% and 72.7% of isolates presenting MDR phenotype among chickens and workers respectively. ESBL phenotype detected in 5.5% (26) of poultry isolates while, none of the workers isolates have this phenotype. Six isolates carried both of TEM and CTX-M whereas, five and one isolates were detected only for TEM and CTX-M, respectively. Eighty-eight and nine-tenths percent of ESBL E. coli displayed AmpC phenotype. CONCLUSIONS: Since cephalosporins are not used in broilers in Iran, isolation of faecal E. coli isolates producing extended spectrum β-lactamases in broilerchickens can indicate transfer of the resistance genes via plasmids and other mobile genetic elements among Enterobacteriaceae.