Background: Antibiotics have long been the first line of defense to prevent Escherichia coli infections, but they have lost their potency since bacteria have grown increasingly resistant to treatment. The present research aimed to study the drug resistance and the prevalence of tetracycline resistance genes in E. coli isolated from broilers with colibacillosis. Results: The results showed that the most prevalent type of drug resistance was to tetracycline at 95.0%, and the least was to gentamicin at 21.7%. The prevalences of antimicrobial resistance among the tested antibiotics were significantly different (p < 0.001). A statistically significant difference was observed between the prevalence of the tet genes (p < 0.001). The tetD positive isolates and antibiotic sensitivity to tetracycline showed statistical significant differences (p = 0.017). Conclusions: Considering the results, tetA is the most common tetracycline resistance gene, and the presence of tetD and antibiotic sensitivity to tetracycline had a significant relationship in E. coli isolated from colibacillosis infections.

lay eggs. Myiasis is described as infection and infestation by fly larvae (maggot) in the organs or tissues of animals and humans. Myiasis may result in organ disfigurations, unpleasant smell, anorexia, and weight loss. In severe cases, toxemia and sepsis caused by secondary bacterial infection are possible (Najjari et al., 2014;Nouri and Salehi, 2020). Based on the target organ, the myiasis is categorized as cutaneous, ocular, urogenital, nasal, auricular, and