Sap11/Sap12 and egc Associated Toxin Genes are Dominant in Slime Forming Clinical Staphylococcus Aureus Isolates Harboring icaABCD-Operon

The prevalence of adhesion (icaA and icaD) and toxin (tst, eta, and etb) genes was studied in100 clinical Staphylococcus aureus isolates. The icaA, icaD, eta, etb and tst genes were detected by PCR in 91%, 91%, 2%, 1% and 43% of the isolates, respectively. Various gene combinations with the previously reported enterotoxin genes (sea, sec, sei, seg and seh) were detected in 47 of 100 isolates. These combinations fall into 3 groups: group I which includes one eta+sea containing isolate, group II which includes 25 (53.2%) isolates lacking tst gene but harboring icaA+icaD genes in 11 combinations with the enterotoxin genes and group III which includes 21 (44.7%) isolates harboring icaA+icaD+tst in 7 different combinations with the enterotoxin genes. The predominant gene combinations in group II and III isolates include seg + sei or seg of the enterotoxin gene cluster (egc). Furthermore, 20 isolates of group III have the corresponding gene combination profiles of 20 isolates of group II in addition to the tst gene. This could be attributed to loss or acquisition of SaPI1 and/or SaPI2 islands which carry the tst gene. The dominancy of SaPI1/SaPI2 and egc associated toxin genes in the slimy isolates of S. aureus may be understood in the context of pathogenicity functioning genes. This data would contribute to the control of colonization and spread of these isolates in hospitals and community at large.