Molecular Epidemiology Based on SPA Genotyping of Staphylococcus aureus Isolated from Cattle and Camels in Egypt

Staphylococcal protein A (SPA) is an important virulence factor of S. aureus and it is considered one of the significant genes that used in the molecular epidemiological investigations. Two hundred forty milk samples were collected from animals with no signs of clinical mastitis; dairy cows (140) and she-camels (100). This study was concerned with the analysis of the molecular characterizations of SPA genes extracted from the whole bacterial chromosome of 13 S. aureus isolates from dairy cows (9) and she-camels (4) raised in Egypt. According to the mecA gene, the S. aureus strains were divided into 7 methicillin resistant S. aureus (MRSA) and 6 methicillin susceptible S. aureus (MSSA). Analysis of the different SPA sequences revealed the presence of 8 SPA types; the most common SPA type was t359 that found in 5 isolates of S. aureus (all of them MRSA). By conducting the multiple sequence alignment, it revealed the presence of 7 conserved regions and 2 highly variable regions. The phylogenetic analysis of the SPA sequences of S. aureus local isolates and those were retrieved from the GENEBANK revealed 2 main clusters; the first one contained all local sequences in addition to EU695225. The rest of retrieved sequences were gathered in the second cluster.