Investigation of methicillin resistance and Panton-Valentine leukocidin in Staphylococci isolated from bovine mastitis

The aim of this study was to isolate the Staphylococcus species from bovine mastitis, investigate the mecA ve pvl genes in isolated species by PCR and determine the antibiotic resistance of methicillin resistant strains to some antibiotics commonly used in veterinary field. In the present study, 972 mammary quarter milk samples were used from 251 lactating cows from 34 different small (family type), mid and large-sized enterprises located center town and villages of Ödemiş, İzmir. After CMT was applied to each mammary quarter, 757 mammary quarter milk samples were found to be CMT positive and 215 mammary quarter milk samples were found to be CMT negative. A total of 182 (18.72%) Staphylococcus strains were isolated from 972 mammary quarter milk samples CMT positive and negative. It was determined that 120 (47.8%) of 251 cows were infected with the least one Staphylococcus species. Of 182 Staphylococcus strains, 137 (75.27%) and 45 (24.73%) were detected as KPS and KNS, respectively. The different 11 Staphylococcus species were isolated in this study. Among the species, S. intermedius (42.30%) was the most common species isolated, followed by S. aureus (32.97%) and S. saprophyticus (10.99%). It was found that 4 (2.2%) of 182 Staphylococcus strains harboured mecA gene and mecA positive 4 strains were S. intermedius. In this study investigating the presence of PVL toxin, pvl toxin gene was found in none of the strains. Antibiotic resistance of 4 methicillin resistant S. intermedius strains to antibiotics commonly used in veterinary medicine were investigated using Kirby-Bauer disc diffusion test. According to test results, all of 4 mecA positive S. intermedius were resistant to penicillin G, oxacillin and cefoxitine. The resistance was also found to erythromycin (50%), rifampicin (25%), gentamicin (25%), tetracycline (25%) and trimethoprim/sulfamethoxazole (25%) in the isolates.