Molecular Characterization of Virulence Genes of Staphylococcus aureus Isolated from Camel Clinical Mastitis in Egypt

Abstract

Background: Staphylococcus aureus (S. aureus) is well-recognized worldwide as one of the main etiological agents of mastitis in dairy animals. The current investigation was undertaken to determine the prevalence and virulence factors of S. aureus isolated from camels with clinical mastitis in Egypt. Methods: A total of 200 milk samples were collected from camels suffering from clinical mastitis and they were examined for S. aureus. Both conventional culture-based methods as well as a molecular-based approach were used to identify the bacterium. S. aureus isolates were further examined by polymerase chain reaction (PCR) assay for the presence of seven virulence genes namely, clumping factor A (clfA), alpha-hemolysin (hla), beta-hemolysin (hlb), toxic shock syndrome toxin-1 (tsst-1) staphylococcal enterotoxin A (sea), intercellular adhesion A (icaA) and intercellular adhesion D (icaD). Result: Out of the 200 samples screened, 60 (30%) were confirmed as S. aureus. All S. aureus isolates (100%) were found positive for cIfA, hlb, icaD and tsst-1 genes. The icaA gene was identified in 2 (10%) isolates, sea gene was detected in 3 (15%) isolates whereas, none of the isolates was found positive for the hla gene. The findings of our study reveal a notable prevalence of S. aureus harbouring virulence genes, indicating a crucial role for these factors in the pathogenesis of camel mastitis.