Are VISA and VRSA isolates resistant to oxacillin?
All VRSA isolates to date have been oxacillin-resistant (i.e., MRSA) and contained the resistance gene mecA. Most VISA isolates were also oxacillin-resistant. However, two VISA isolates became oxacillin-susceptible upon repeat isolation from the patient and one was oxacillin-susceptible but contained mecA.