Coexistence of virulence genes in methicillin-resistant staphylococcus aureus clinical isolates

Abstract

Introduction: The pathogenic versatility of Staphylococcus aureus is attributed to various virulence genes, including enterotoxins and hemolysins. Methods: Here, the virulence genes in 177 nosocomial MRSA strains in Porto Alegre, Brazil were detected by PCR. Results: The overall prevalence rates were as follows: sea, 4.5%; pvl, 18.6%; tst, 27.7%; hla, 87.6%; and hld, 90.4%. No strain contained all tested genes. However, there was frequent coexistence of tst with pvl and hla with hld (40.7% and 26.6%, respectively). Conclusions: Horizontal transfer of virulence genes is very common in S. aureus, as suggested by the frequent coexistence of several virulence genes.