
Staphylococcus aureus with intermediate-level (VISA) or high-level resistance (VRSA) to vancomycin are must be reported to the local department of health within 24 hours of diagnosis. VISA is S. aureus with a vancomycin MIC >= 4 ug/ml; VRSA is S. aureus with a vancomycin MIC >= 16 ug/ml. Susceptibility levels are defined by according to Clinical and Laboratory Standards Institute's Performance Standards for Antimicrobial Susceptibility Testing; Seventeenth Informational Supplement (M100-S17).