Structural and topological differences between a glycopeptide-intermediateclinical strain and glycopeptide-susceptible strains of Staphylococcus aureus revealed by atomic force microscopy

Novel cell surface topography was revealed on cocci from a glycopeptide-int ermediate Staphylococcus aureus (GISA) clinical strain by using atomic forc e microscopy. The GISA isolate and its revertant had two parallel circumfer ential surface rings. One equatorial surface ring was observed in control s trains. In vancomycin susceptible strains, additional rings were formed in the presence of vancomycin. Ring depth measurements also revealed striking differences between the GISA strain and susceptible strains grown with or w ithout vancomycin.