الفهرس 
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Abstract
In this work 106 isolates were identified as S.aureus with an incidence of 19.13% from the tested mastitic milk samples. RPLA results showed high incidence of type C enterotoxin followed by type A and the type B with an incidence of 34 (32.1%), 19 (17.9%) and 15 (14.2%) respectively. Toxigenic S. aureus isolates produced golden yellow, creamy and white colonies on agar in percent of 69.11%, 27.94% and 2.94% respectively. The present investigation was used to determine types of hemolysis among the S. aureus isolates. Regarding to hemolytic activity of S. aureus isolates on sheep blood agar, it was found that 92.65% of toxigenic S. aureus isolated from bovine milk samples were hemolytic. Out of 68 isolates of toxigenic S. aureus isolates 46 (67.65%) were DNase positive. Almost S. aureus isolates were able to reduce tellurite to metalic tellurium producing black coloration. Out of 68 isolates of toxigenic S. aureus isolates, 66 were positive with a incidence of 97.06%. Three characteristic appearances were recorded among S. aureus isolates after having been grown on crystal violet agar medium. 23.53% of the isolates yielded yellow colonies, 64.71% yielded violet colonies, while 11.76% yielded white colonies from the toxigenic S. aureus isolates. It is clear that most of bovine isolates yielded violet colonies on the medium. Out of 68 isolates of toxigenic S. aureus isolates 51 (75%) showed SpA by agglutination test positive. A total number of 8 isolates were previously proved to be toxigenic isolates by using RPLA, were confirmed to be toxigenic by using PCR as recent technique confirmatory test and the results were discussed completely.