title: Phenotypic and genotypic detection of virulence factors of Staphylococcus aureus isolated from clinical and subclinical mastitis in cattle and water buffaloes from different farms of Sadat City in Egypt.
abstract: OBJECTIVE
  To characterize Staphylococcus aureus from clinical and subclinical mastitis and identify virulence factors.
  
  
  METHODS
  Two hundred and two milk samples were collected, 143 from mastitic cattle and buffaloes 94 and 49, respectively, and 59 from apparently healthy cattle and buffaloes 35 and 24, respectively.
  
  
  RESULTS
  California mastitis test was applied and positive prevalence were 91.48% and 75.51% for cattle and buffalo with clinical mastitis and 37.14% and 45.83% for cattle and buffalo with subclinical mastitis. S. aureus was isolated from clinically mastitic cattle and buffaloes were 39.29% and 50%, respectively. While, from subclinical mastitic cattle and buffaloes were 80% and 72.73%, respectively. Hemolytic activity was assessed for S. aureus isolated from clinically and subclinical mastitic cases with prevalences of 100% and 56.25%, respectively. Thermo nuclease production from clinically and subclinical mastitic cases was 25% and 56.25%, respectively. Simplex polymerase chain reaction (PCR) conducted on S. aureus using 16S rRNA, clumping factor A, Panton valentine leukocidin, coagulase (Coa), alpha-hemolysin and beta-hemolysin those proved existence in 100%, 46.9%, 65.6%, 100%, 34.4%, and 43.75% of the isolates, respectively. While, multiplex PCR is utilized for detection of enterotoxins and proved that 12.5% was positive for enterotoxine Type D.
  
  
  CONCLUSIONS
  It is concluded that simplex and multiplex PCR assays can be used as rapid and sensitive diagnostic tools to detect the presence of S. aureus and characterize its virulence factors that help in detection of severity of infection, distribution and stating preventive and control strategies.
authors.affiliation: Department of Bacteriology, Mycology and Immunology Faculty of Veterinary Medicine University of Sadat City, Menoufia 32897, Egypt.
authors.forename: Mohamed Sabry
authors.initials: MS
authors.lastname: Elsayed
authors.affiliation: Department of Food Hygiene and Control, Faculty of Veterinary Medicine University of Sadat City, Menoufia, 32897, Egypt.
authors.forename: Abd Elrahman
authors.initials: AE
authors.lastname: Mahmoud El-Bagoury
authors.affiliation: Library of Faculty of Veterinary Medicine, University of Sadat City, Menoufia, 32897, Egypt.
authors.forename: Mai Abdallah
authors.initials: MA
authors.lastname: Dawoud
keywords: Staphylococcus aureus; clinical and subclinical mastitis; enterotoxins; identification; polymerase chain reaction; virulence factors