Inroduction & Objective: Antibiotic resistance can complicate the treatment of infectious diseases of livestock and poultry. The aim of this study was to determine the frequency of genes encoding resistance to quinolones and sulfonamides in Escherichia coli (E. coli) isolated from pericarditis and periphepatitis lesions in broilers to provide a suitable background for treatment with these drugs in these lesions.
Material and Methods: In this study, for detecting of resistance genes to fluoroquinolones and suvanamides, 50 bacterial strains were isolated from broiler chickens with pericarditis and periphepatitis and E. coli colonies were confirmed by microbial and biochemical tests. Then, the resistance of the strains to the commercial antibiotics (Enrofloxacin and sulfonamide + trimethoprim) was evaluated by the conventional antibiogram method. In addition, the bacterial genome was extracted by boiling method and the qnrA and sul1 genes were amplified with specific primers to evaluate antibiotic resistance against fluoroquinolones and sulfonamides.
Results: In this study, 54% of enrofloxacin-resistant strains possed qnrA gene and 48% of sulfonamide-resistant strains plus trimethoprim contained sul1 gene. In this study, resistant strains without studied resistance genes were also found, which indicates the importance of other resistance genes in the development of resistance against sulfonamides and fluoroquinolones.
Conclusion: Evaluation of antibiotic resistance against enrofloxacin and sulfonamides is not possible with the help of one gene and to accurately determine antibiotic resistance, routine phenotypic tests are more effective than detecting a specific gene.
Manuscript profile
