Mastitisli Sığırlardan İzole Edilen Stafilokoklarda Antibiyotik Direnci ve Virülens Gen Profilleri

Abstract

Staphylococcus spp. are the important bacterial agents of subclinical and clinical mastitis cases. This study was aimed to determine the vancomycin resistances, antibacterial resistance profiles, some virulence genes, and pheno- and genotyping of staphylococci from mastitis. For this aim, 121 staphylococcal isolates were analyzed. The identifications of isolates were confirmed with PCR for being Staphylococcus spp. and Staphylococcus aureus. The antibiotic resistance patterns were determined by Kirby bauer Disc Diffusion Tests and according to the resistance profiles, the isolates were antibiotyped. The vancomycin resistance genes were determined by PCR for investigating the vanA, vanH, vanR, vanS, vanZ, vanY and vanX genes. The vancomycin resistant isolates were genotyped with RAPD-PCR. The nuc gene was detected in 86 of 121 staphylococcal isolates examined and named as Staphylococcus aureus. The remaining 35 isolates were defined as Staphylococcus spp. S. aureus isolates were found to be resistant to penicillin G, amoxicillin/clavulanic acid, oxacillin, tetracycline, cefaperazone, teicoplanin, vancomycin and trimethoprim-sulfomethaxazole at 50% (43/86), 40.7% (35/86), 34.9% (30/86), 23.3% (20/86), 22.1% (19/86), 18.6% (16/86) 10.5% (9/86) and 8.1% (7/86) respectively. On the other hand, 4 (11.4%) of 35 Staphylococcus spp. isolates were resistant to penicillin G, 3 (8.6%) to amoxicillin/clavulanic acid, 2 (5.7%) to trimethoprim-sulfometaxazole, 1 (2.9%) to oxacillin, cefaperazone, teicoplanin, while all isolates were sensitive to vancomycin and tetracycline. Of the 9 S. aureus isolates that were phenotypically resistant to vancomycin, vanA gene was detected in 2 and vanR gene in 3 isolates. Multiple resistances to three or more antibiotics were determined in 42 of 86 S. aureus isolates. In addition, coa gene was detected in 61 (70.9%) of 86 S. aureus isolates. 10 different gene polymorphisms were detected in coa gene positive isolates. While the spa gene was determined in all S. aureus isolates, it was revealed that they had 4 spa gene polymorphisms. Nine different genotypes with a similarity between 51-75% were detected in the genotyping of vancomycin resistant 9 isolates. In conclusion, multiple antibiotic resistance rates in S. aureus isolates investigated were found to be important for mastitis treatment. The results obtained from this study show that milk and dairy products containing these factors pose a public health risk due to the determination of vancomycin resistance in mastitis-derived Staphylococcus strains.