Vancomycin resistance in S. aureus is an emerging problem and a dangerous development. S. aureus infections, including skin and soft tissue infections are very common, as are invasive bloodstream infections among hospitalized persons. Treatment of invasive S. aureus infections has increasingly relied on vancomycin because of widespread S. aureus resistance to other antibiotics. Fortunately, VRSA remains rare, however, VISA is becoming increasingly common in Georgia and many other places.

VISA and VRSA are defined by the minimal inhibitory concentration (MIC) of vancomycin; that is, the amount of vancomycin that will stop them from growing. The isolate is VISA If the vancomycin MIC is 4-8 μg/ml, and the isolate is VRSA if the MIC is >16 μg/ml.

Testing for vancomycin resistance can be problematic, making it important that suspected VISA/VRSA isolates are confirmed by a reference laboratory. At this time, only isolates that have an MIC of at least 8µg/ml can be submitted for additional testing. All such isolates should be submitted to the Georgia Public Health Laboratory.

Vaccination & Prevention

There is no vaccine to prevent S. aureus infections. Because S. aureus are typically carried in the nose and on the skin, general prevention measures include covering coughs and sneezes, good hand hygiene, and covering open wounds to prevent contamination. Personal items that contact skin (such as towels, razors, or bar soap) should not be shared. Antibiotic use promotes carriage of and infection with bacteria that are antibiotic-resistant. Unnecessary antibiotics should be avoided for this and other reasons, such as cost, side-effects, and allergies.

More about VISA/VRSA:

Investigation and control of vancomycin-intermediate and -resistant S. aureus: A Guide for Health Departments and Infection Control Personnel

Updated 12/27/2022