Mastitis in dairy cow farms in canton Sarajevo and antimicrobial resistance of causative agents

Mastitis is frequent and costly disease in dairy farming, while antimicrobial resistance is an important public health threat. Increasing resistance among zoonotic pathogens led to more investigation among animal pathogens. Study, conducted on dairy farms in Canton Sarajevo, aimed to establish mastitis prevalence in dairy cows, causative bacteria and investigate antimicrobial resistance. Lactating animals (n=1214) were tested using the California Mastitis Test during November 2017. Milk from positive animals was microbiologically cultivated. The overall prevalence of mastitis was 9.9 %, while 19 out of 180 dairy farms had at least one mastitis case. In 49.2% of samples, we identified S. aureus, 2.5% contained E. coli, 0.8% contained Enterobacteriaceae, 13.3 % had mixed infection and 34.2% samples had no growth. Using disk diffusion test highest resistances were observed to bacitracin (E. coli), trimethoprim/sulfamethoxazole (Enterobacteriaceae) and penicillin (S. aureus). Since oversight on antimicrobial use in farm animals is sporadic in the country, additional investigations of antimicrobial usage and trends in antimicrobial resistance causing agents are needed. Reducing mastitis rates on farms requires compliance with preventive measures alongside early detection, isolation of cases, culling of repeated cases, microbiological monitoring and testing for antimicrobial resistance before treatment.