Morphological and genetic differences in two isogenic Staphylococcus aureus strains with decreased susceptibilities to vancomycin.

Many VISA (vancomycin intermediately resistant Staphylococcus aureus) strains are characterized by increased cell wall biosynthesis and decreased cross-linking of the peptide side chains, leading to accumulation of free D-alanyl-D-alanine termini in the peptidoglycan, which act as false target sites for vancomycin. A spontaneous mutant of methicillin… CONTINUE READING