Phenotypic and genotypic features of Staphylococcus aureus strains isolated from cattle and humans

Abstract

The aim of this study was to determine susceptibility patterns of S. aureus strains (46 were isolated from bovine milk samples with mastitis, 35 from bovine teat skins, 3 from bovine noses, 3 from caretaker hands and 3 from caretaker noses) to various antibiotics by E-tets and was to define genotypic characteristics of these isolates by plasmid and Pulsed Field Gel Electrophoresis (PFGE) analyses. According to E-test results, the percentages of S. aureus isolates resistant to penicilin G, tetracycline, erythromycin, oxacilline and enrofloxacin were found to be 85.4% (82), 39.6% (38), 5.2% (5), 3.1% (3) and 1.0% (1), respectively. Nine different types were determined in the plasmid analyses of the isolates. In 87 (90.6%) of the isolates, 10 different types of plasmids with the sizes between 1.8-19 kb were determined while no plasmid was detected from the 9 (9.4%) of the isolates. Genetic relationships among S. aureus isolates were performed using PFGE method and 42 distinct PFGE patterns were identified. Strains were assigned as 13 major lineage groups (A, B, C, D, E, F, G, H, I, J, K, L, M) with respect to the genetic relationships. 58.3% (56 samples) of strains were clustered as pulsotype A. In conclusion, according to plasmid analysis and PFGE data, a clone of S. aureus was broadly detected in dairy farms in Kirikkale province.