VIRULENCE FACTORS OF STAPHYLOCOCCUS-AUREUS STRAINS CAUSING INFECTIVE ENDOCARDITIS - A COMPARISON WITH STRAINS FROM SKIN INFECTIONS

The objective was to study potential bacterial virulence factors in S. aureus endocarditis. S. aureus strains isolated from patients with we ll-classified episodes of infective endocarditis (IE) (n=26) were comp ared with control S. aureus strains from consecutive patients with ski n infections (n=30). The potential virulence factors studied were Stap hylococcal enterotoxin A-D (SEA, SEE, SEC, SED) and toxic shock syndro me toxin-1 (TSST-1) production and binding capacity to the extracellul ar matrix proteins: fibronectin, collagen type I, collagen type II and bone sialoprotein (BSP). None of the potential virulence factors stud ied was more prevalent among the IE strains. BSP binding was more ofte n found in the control group with skin infections. Endocarditis patien ts with previous damage of the heart Valves were more often infected b y strains not producing any enterotoxin. No correlation was found betw een the potential bacterial virulence factors studied and IE. Concerni ng the toxins known to act as superantigens (SEA-E and TSST-1), the te ndencies in this and other studies indicate that a larger study group might identify them as pathogenic factors in a subgroup of staphylococ cal endocarditis.