Identification of bacteria isolated from dairy goats with subclinical mastitis and investigation of methicillin and vancomycin resistant staphylococcus aureus strains

Abstract

The objective of this study was to determine methicillin and vancomycin resistance phenotypically by agar disc diffusion method (ADDM) and minimal inhibitory concentration (MIC) test and genotypically by polymerase chain reaction (PCR) in Staphylococcus aureus strains isolated from goat milk. A total of 466 milk samples were collected from 233 goats in herds with mastitis problems in Burdur province of Turkey. The microorganisms were isolated from 122 (26.18%) of goat milk samples and among these microorganisms 53 (42.06%) were coagulase negative staphylococci (CNS), 43 (34.23%) were Staphylococcus aureus, 16 (12.08%) were Escherichia coli, 10 (7.94%) were Candida spp. and 4 (3.17%) were Brucella melitensis. Seven of S. aureus isolates were determined resistant to methicillin by ADDM and five of these isolates were found resistant to methicillin by MIC. mecA and vanA genes can not be determined in S. aureus isolates by PCR. Staphylococcus aureus isolates were found to be susceptible to vancomycin by ADDM and MIC test. In conclusion, S. aureus and CNS are found to be the most isolated species from goat milk in Burdur province. In addition to that, the absence of mecA and vanA genes in the S. aureus isolated from goat milk showed that goat milk does not play a significant role in the spreading of MRSA.