Molecular analysis of Coagulase Gene in Enterotoxigenic Staphylococcus aureus strains

Coagulase enzyme is one of the most important virulence factors of Staphylococcus aureus (S. aureus), which could be used for differentiation of S. aureus from other Staphylococcal species. The relationship between the genotype of coagulase and the enterotoxigenic strain of S. aureus is unknown. The purpose of this study was to investigate coa gene typing in enterotoxigenic strain of S. aureus. A total of 21 enterotoxigenic S. aureus strains were assayed. A specific pair primer for coa gene amplification was selected. Gene extraction from the bacterial strain was carried out separately. Then, the coa gene amplification by PCR was performed. Using the bioinformatics methods in Silico and comparing PCR products with reference samples in silico, the search for AluI restriction enzyme digestion sites was determined. The results of coa gene amplification showed that only 20 S. aureus strains have this genetic element and consist of eight classes of coa gene based on their size, ranging from 352 to 1200 bp amplicons. All amplified fragments have fragments restriction enzyme AluI site action except fragment 352 bp which prone to genotyped. The frequency of the coa genotype in this study was type I (42.85%), type IV (19%), type II (9.5%) and others (4.76%) respectively. The results of alignment coa gene types with enterotoxigenicity showed that the potent enterotoxin producer was related to coa gene type II and VI. The study results indicated that the coa gene by primer pairs could have an amplified different size fragment. The comparison finding with references is a simple and accurate method for genotyping of the S. aureus isolate and it would be able to determine the type of enterotoxins produced.