Antibiotic resistance pattern and presence of biofilm producing ica operon virulence genes in coagulase positive Staphylococcus aureus isolated from bovine mastitis in East Azerbaijan province

Staphylococcal mastitis is one of the most important diseases in industrial livestock and Staphylococci capable of producing biofilm, micro and macro abscesses, are considered to be the cause of malignant mastitis which result in culling of dairy cattle. The ability of these bacteria to produce biofilm depends on the presence of ica operon genes (icaA, icaB, icaC, icaD and icaR) and also some environmental factors. In the present study, the pattern of antibiotic resistance and the presence of operon ica virulence genes in Staphylococcus aureus isolated from bovine mastitis was investigated. According to the findings of microbiological and simplex PCR tests, it was determined that in the farms tested in East Azerbaijan province, Staphylococcal mastitis has a relatively high prevalence and among the relevant isolates, a relatively high percentage of them contain a variety of operon ica virulence genes that encode the ability to produce biofilm. Also, the results of antibiotic susceptibility testing performed on these isolates showed that they were more resistant to most of the antibiotics tested. Due to the high presence of ica operon genes, especially genes such as icaA and icaD, which result in production of stronger and excessive biofilm as well as increased resistance to various antibiotics, the results of the present study therefore indicate an unfavorable prognosis regarding the success of antibiotic treatment of staphylococcal mastitis in livestock farms in the region.