Phenotypic and genotypic resistance of Escherichia coli isolated from broiler chickens of Urmia to sulfonamides

Colibacilosis is one of the most important infectious diseases in poultry industry. Antibiotics are the most important tool in dealing with the treatment and control of the disease. Checking the sensitivity of bacterial isolates to antimicrobial compounds, before choosing an antibiotic drug in the region is essential. In this study, phenotypic resistance profile of 44 isolates of Escherichia coli recovered from broiler chickens of Urmia city suspected to colisepticemia to Sulfadiazine evaluated by disk diffusion method. Genotypic resistance profile was also assessed by Polymerase Chain Reaction (PCR) of Sul1 gene. Results showed that 20 (45.5%) Escherichia coli isolates were resistant to sulfadiazine and Sul1 gene was detected in 25 (56.8%) isolates. Five isolates that had the Sul1 gene showed no antibiotic resistance in antibiogram test. The results showed that the resistance rate of isolates to sulfonamides was high and sul1 gene had a major role in sulfadiazine resistance of these isolates.