Antimicrobial Resistance Genes of E. coli Isolated from Broiler Chickens in Upper Egypt

The background: E. coli infection is a septicemic disease with an economic importance of poultry causing multiple lesions in broiler chickens. Recent reports described increased resistance of E. coli to many antimicrobial agents. This research work aimed to detect, identify and study antimicrobial resistance genes of E. coli isolated from broiler chickens in Upper Egypt. Methods: Three-hundreds samples, including 200 liver and 100 tracheal swabs, were collected from broiler chicken flocks at different localities in Assiut and El-Minya Governorates. Samples were subjected to isolation and phenotypic identification, serological typing, detection of sensitivity and resistance to antimicrobial drugs and determination of genes responsible for resistance to antimicrobial agents. Results and conclusion: revealed that E. coli could be isolated and phenotypically identified with a percent ratio 70% (210 from 300). Twenty-six out of 30 E. coli isolates were serologically identified. Determination of antimicrobial susceptibility and resistance patterns of E. coli isolates to variable antimicrobial drugs using standard disk diffusion and minimum inhibitory concentration (MIC) methods was done. Detection of antimicrobial resistance genes of 12 serologically identified E. coli isolates showed that ƒloR gene (Florfenicol resistance gene) was detected in 6 isolates and strA-strB gene was detected in 5 isolates, while aadA gene was detected in all 12 isolates. Both strA-strB and aadA are streptomycin resistance genes.