Distribution of Antibiotic Resistance Genes in Enterococcus spp. Isolated from Mastitis Bovine Milk
AbstractIn this study, determination of enterococcus species that were isolated from mastitic milk samples, investigation of their susceptibilities to antibiotics and identification of the existence of resistance genes in resistant strains were conducted. The specimens consist of 600 mastitic milk samples that were collected from 242 cows. Isolation of enterococcus was carried out in selective media and 94 (15.6%)Enterococcusspp. were isolated. A total of 94 species of Enterococci were identified using both sequencing and polymerase chain reaction (PCR).Enterococcusspp. isolates belong to 5 different species (E. faecalis, E. faecium, E. durans, E. hirae, E. mundtii) in sequence analysis and 4 different species (E. faecalis, E. faecium, E. durans, E. hirae) were identify by PCR method with specific primers. Analyzing 94 enterococcus strains by antibiotic sensitiveness test a high rate of resistance to tetracycline in 77 (81.9%) isolates was shown. Thetetresistance genes were identified as follows: 54 weretetM positive, 23 weretetK positive and 17 were positive ontetM andtetK. Resistance to erythromycin was established in 27 (28.7%) isolates (25ermB) while the chloramphenicol resistance gene was found in 10 (10.7%) of isolates and thecatgene was identified in nine samples and one isolate was resistant to vancomycin (1.06%) with theVanA gene confirmed. In conclusion, it was shown thatE. faecalishas the biggest role inenterococcusoriginated mastitis and these strains were found to be mostly resistant to tetracycline. One vancomycine resistant isolate that had theVanA gene was also determined.