Insights into the molecular basis of reduced vancomycin susceptibility among three prominent Staphylococcus aureus clonal complexes

Staphylococcus aureus is a leading cause of healthcare-associated infections globally. Vancomycin resistant S. aureus (VRSA), those with high-level resistance (MIC of 16-32 ug/ml vancomycin), are uncommon, whereas vancomycin intermediate S. aureus (VISA, MIC of 4-8 ug/ml), are isolated more frequently and develop during long-term and/or repeated use of the antibiotic. VISA can be difficult to eradicate and infections may persist. Our knowledge of mechanisms that underlie development of VISA is incomplete. We used a genomics approach to investigate the VISA phenotype in three prominent S. aureus lineages.