Phenotypic and genotypic characterization of S. aureus isolated from clinical and subclinical bovine mastitis

الملخص EN

In order to determine the prevalence of S.

aureus in clinical and subclinical bovine mastitis as well as the relationship between the presence of protein A gene and the udder inflammatory response .

A total of 400 quarter milk samples were collected from 100 lactating Friesian cows at Ismailia Governorate .

The percentage of clinical mastitis was ( 19.5%.), while the percentage of subclinical mastitis according to C.M.T was ( 42.85%) .

The percentage of S.aureus in clinical mastitis was (28.2%) , while in in subclinical mastitis was (22.46% ).The identification of S,aureus was confirmed by PCR amplification of species-specific parts of the gene encoding the 16S rRNA.

Twenty nine S.aureus isolates were subjected to PCR for detection of X region of protein A (spA) gene,10 isolates from clinical mastitis and 19 isolates subclinical mastitiC milk specimens (+++ve CMT and ++ve CMT) were (100%) positive .

Results indicate that there was a positive relationship between the presence of protein A gene of S.aureus and the inflammation of udder in clinical mastitis as well as the high grades of subclinical mastitis.