Crystal Violet Binding, Cell Surface Properties and Extracellular Enzyme Profiles of Staphylococcus aureus Producing Toxic Shock Syndrome Toxin-1

Abstract

Staphylococcus aureus isolated from clinically diagnosed cases of toxic shock syndrome (TSS) showed susceptibility to phage types belonging to both I and III groups (90.5%). Phage typing patterns showed a wide diversity among 87 toxic shock syndrome toxin-1 (TSST-1) positive strains isolated from different non TSS clinical sources. Toxin producing strains isolated from both TSS and non TSS showed a remarkable ability to bind to crystal violet (pattern C/D, 97.2%) incorporated into brain heart infusion agar media at subinhibitory concentrations and these isolates were traced to biotype var. hominis. The cellular fatty acid compositions of TSS and non-TSS strains belonging to the three biotypes S. aureus var. hominis, S. aureus var. bovis and S. aureus var. canis did not differ. TSST-1 producing strains demonstrated a high salt aggregation test value (above 1.5) indicating a low cell surface hydrophobicity. Both TSS and non TSS strains demonstrated a high lipolytic activity. TSST-1 positive strains in general, showed significantly higher lipase activity than strains isolated from septicemia (p less than 0.0001) and superficial (p less than 0.0001) infections. The proteolytic activity is higher among TSS (median value 0.075 U/ml) than to non TSS (median value 0.045 U/ml) strains. There was no correlation with the quantity of toxin production in vitro and to the properties described.