Characterization of a Daptomycin-Nonsusceptible Vancomycin-Intermediate Staphylococcus aureus Strain in a Patient with Endocarditis

We analyzed the emergence of daptomycin nonsusceptibility in a patient with persistent vancomycin-intermediate Staphylococcus aureus (VISA) bacteremia. The daptomycin-nonsusceptible VISA's cell wall demonstrated a reduction in muramic acid O-acetylation, a phenotypic parameter not previously reported for VISA; some isolates also contained a single point mutation in the mprF gene.