organism: Staphylococcus aureus
description: VRS3a is in most aspects the same as VRS3b, but the vancomycin resistant phenotype for VRS3a is less stable than that of VRS3b. For stability purposes, it is recommended that VRS3a be subcultured in the presence of vancomycin. Unstable VRSA, cream (lt. orangish-white) colonies, robust growth; VRSA 3a, HIP13170