Comparison of different methods in the identification of Staphylococcus aureus in cattle


This study aimed to compare the efficiency of conventional microbiological, Miniaturizekit GP24 and molecular technique by using PCR of nuc gene in the identification of S. aureus.Also to evaluate the efficiency of the tube coagulase and DNase activity tests. 104 of suspected S.aureus was isolated from different cattle samples, (68.3%) and (75%) were positive forcoagulase and DNase tests, respectively. The sensitivity and specificity of coagulase andDNase were 92.5%, 75.7% and 79.1% , 32.4% respectively. The identification rate of S.aureus by GP24 kit and PCR detection using nuc gene was 68.26% and 64.42% respectively.Out of 104(31.7%) of isolates were identified as coagulase-negative staphylococci by usingGP24 kit. Antimicrobials susceptibility assays of 67 S. aureus isolates revealed that, theThe highest resistance rates were against penicillin (97%) followed by tetracycline (25.4%).While all isolates were found to be highly sensitive toward Imipenem, vancomycin, andchloramphenicol (100%) for each. In conclusion, the coagulase and conventionalmicrobiological techniques have more reliable results in comparison with the DNase test forthe identification of S. aureus. On other hand, the results of the GP24 kit and coagulase tube testwere similar in sensitivity and specificity.