The frequency of tetracycline resistance genes in Escherichia coli strains isolated from healthy and diarrheic pet birds

Document Type : Short paper


Department of Clinical Sciences, Faculty of Veterinary Medicine, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran



Background: Pet birds have close contact to human and resistant bacteria can transfer from birds to intestinal flora of human. Aims: This study was carried out to determine the tetracycline resistance genes in Escherichia coli (E. coli) strains associated with enteric problem in pet birds. Methods: Totally, 295 cloacal swabs were collected from 195 healthy and 100 diarrheic pet birds in Isfahan province, Iran. The presence of E. coli was identified by conventional bacteriological, biochemical and molecular examination. The presence of tetracycline resistance genes (tetA, tetB, tetC, tetD, tetE, tetG, tetK, tetL, tetM, tetO and tetS genes) were examined using three multiplex PCR. Results: The results showed that in healthy and diarrheic pet birds, 18.9 and 43 percent of cloacal samples, contained E. coli, respectively. The mean percentage of E. coli isolated from cloacal samples of diarrheic birds was significantly higher than the healthy birds (46.6 vs 23.1 percent). In healthy birds from 37 E. coli isolates, 10 isolates were resistant to tetracycline which contained tetA and tetB genes (3 tetA vs 7 tetB), but in the diarrheic birds of 26 resistance E. coli, 11, 12 and 3 strain contained tetA (42.3%), tetB (46.15) and tetA+tetB (11.53%) genes. The percentage of tet genes in diarrheic birds significantly higher than healthy birds (58.9 vs 24.0 percent). Conclusion: Both resistant genes of tetA and tetB were detected in E. coli isolates that is related with efflux pump activity.  These genes can be transferred between Gram negative bacteria and has the potential ability to transfer to the environment and human flora.


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