Phenotypic and genotypic characterization of Staphylococcus aureus isolated from mastitis cases of cows and buffaloes
Abstract
The present investigation was carried out to characterize 126 Staphylococcus aureus isolates isolated from 1230 mastitic milk samples of buffaloes and cows. Phenotypic characterization included tube coagulase test, thermostable nuclease test and latex agglutination test. Genotypic characterization involved polymerase chain reaction (PCR) assay based on the nuclease gene (nuc) encoding thermostable nuclease enzyme. Among phenotypic tests, thermostable nuclease test was found to be most sensitive. As many as 97.62% of isolates were found positive for nuclease gene (nuc) with amplified product of size 270 bp. Thus, PCR assay was found to be most rapid, sensitive and specific assay for accurate identification of Staphylococcus aureus up to species level as compared to other phenotypic tests and represents an innovative diagnostic tool for screening of large number of staphylococcal isolates.
Keywords
Mastitis, Staphylococcus aureus, coagulase, thermonuclease, latex agglutination, PCR