[Clinical microbiological investigation of vancomycin intermediate Staphylococcus aureus during glycopeptide therapy].

We isolated three strains of vancomycin intermediate Staphylococcus aureus (VISA) from a blood sample of a patient with infective endocarditis (VISA-1), postoperative pneumonia sputum (VISA-2), and pyogenic spondylitis blood sample (VISA-3). These VISA strains did not carry vanA, vanB, vanC1, or vanC2/C3 genes. Cell wall thickening was observed. VISA-1 and VISA-3 PFGE patterns showed the completely same pattern compared to the PFGE pattern of methicillin-resistant Staphylococcus aureus first isolated from patients 1 and 3. After 10 days on brain heart infusion agar, wall thickening in all three type of VISA was unchanged, but VISA-2 and VISA-3 reversed vancomycin susceptibility. The most suitable use of vancomycin in patients with MRSA infection thus appears to be in reducing the opportunity for cell wall thickening.