Molecular Basis of Tetracycline Resistance in Escherichia coli Isolates Recovered from Poultry Drinking Water

The present study was carried out to examine the molecular basis of tetracycline resistance in the E. coli isolates recovered from poultry drinking water. Samples (n=50) were collected from poultry drinking water and processed for microbial and biochemical characterization. Antibiotic resistance of E. coli isolates was examined by disk diffusion method. Twenty five tetracycline resistant E. coli were isolated using 30 mu g/mL antibiotic, in the growth medium. Plasmid DNA was extracted from the resistant isolates. The tetracycline resistance genes were amplified and sequenced. The prevalence of tetA, tetB, tetC, tetD, tetE and tetG genes was examined. The results demonstrated that 32% of the total isolates contained tetA gene where as 68% contained both tetA and tetB genes together. None of the isolates contained the tetC, tetD, tetE and tetG gene alone or in combination. We reported the existence of more than one tet genes in the same strain at a frequency higher than that reported in previous studies. (C) 2014 Friends Science Publishers