Evaluation of antimicrobial resistance in Staphylococcus Spp. isolated from subclinical mastitis in cows

The objective of this study was to determine the antibiotic resistance in different staphylococcus isolates using conventional and molecular methods. a total of 61 subclinical mastitis isolates of staphylococci were evaluated for oxacillin,erythromycin,tetracycline,nitrocefin,and cefoxitin using the kirby-bauer disc diffusion method. the same isolates were also subjected to the multiplex pcr technique to detect meca,fema and erma,ermc,tetk,and tetm genes. of the isolates,(staphylococcus aureus,n=34 and coagulase negative staphylococcus (cons),n=27) 26,29,and 8 were resistant to erythromycin,tetracycline,and oxacillin,respectively in phenotypical evaluation. the genotypical evaluation indicated that of the strains,34 carried erm genes in erythromycin-resistant strains and 10 carried tet genes in tetracycline-resistant strains. agreement rates between genotypic and phenotypic evaluation for erythromycin,tetracycline and methicillin were 57,65.5 and 89% respectively. data suggest that phenotypical methods should be accompanied by genotypical methods to establish antibacterial resistance accurately,which would enhance treatment efficiency. ©2015 pvj.