Survey and identification of Resistance Genes of Sulfanamide (sul2, sul3) and Tetracycline Tet (A), tet (C), tet (D) and intI Integron Genes in Escherichia Coli Isolated from Mastitis Samples

Escherichia coli is a natural microflora of the human heart and all the warm animals. Mastitis is a disease caused by various pathogens. One of the important factors in the production of mastitis in the livestock is E. coli and is known as peripheral mastitis. The aim of this study was to isolate sulfonamide, integron and tetracycline resistance genes in E.coli isolated from mastitis with clinical symptoms using Multiplex PCR.

50 milk isolates with mastitis symptoms were collected from livestock farms in west of Tehran. Biochemical and microbial tests were performed and antibiotic susceptibility test using disc diffusion method was performed according to CLSI 2016 and E-test with antibiotics of different groups. After isolating the bacteria and extracting DNA, the presence of the genes was investigated by Multiplex PCR.

Based on the findings of this study, out of a total of 50 samples, 1 sample (2%) had Sul2 gene and 32 samples (64%) had the tetA gene and 11 samples (36%) of the tetc gene. Also Int gene was detected in 1 sample of 2% of the samples and the highest antibiotic resistance to the antibiotic sultrim and cotrimoxazole were 68% and 50%, respectively, and the highest sensitivity to tetracycline was 96%.

Comparison of this study with other studies has shown that the resistance gene in E.coli isolated from mastitis is high. The difference between the results of the M-PCR method in this study and the results of studies by other researchers in different parts of the world may be due to the source of the sample, while in studies of other researchers, most cases have been studied on samples of blood diarrhea. Another reason for the difference is the difference in geographical areas.