Abstract Staphylococcus aureus is a major cause of bovine mastitis and it causes huge economic losses in dairy herds. In dairy cattle, this bacterium is frequently associated with various type of bovine mastitis, and may contaminate milk and other dairy products. The objective of the present study was to evaluate the occurrence of S. aureus in milk obtained from bovine farms located in the regions of Hamedan, Iran. In presence study the correlation rate of S. aureus presence with level of milk somatic cells and with CMT results was evaluated. A total of 36 samples (bovine raw milk) were collected. Staphylococcal isolates were identified on the basis of cultural and biochemical features such as, cultural characteristics on differential media (blood agar, mannitol salt agar and DNase agar) and biochemical tests (catalase, oxidase and coagulase). SCC and CMT were performed according to what previously described. The correlation between SCC and CMT with S.aureus presence was calculated by Spearman's rank correlation test. On the basis of cultural and biochemical features, out of 36 milk samples 2 S.aureus (5.55%) isolated. In total 26 samples (72.22%) has high CMT value. in subject to SCC test, 28 samples (77.77%) were positive, 4 samples (11.11) were moderate and 4 samples (11.11) were negative. It should be noted that significant correlation between CMT, SCC and Staphylococcal presence was not observed.
