Vancomycin intermediately resistant Staphylococcus aureus
Vancomycin intermediately resistant Staphylococcus aureus (VISA) is a mutation of a bacterium that’s spread easily by direct person-to-person contact. It was first discovered in mid-1996 when clinicians found the microbe in a Japanese infant’s surgical wound. Similar isolates were reported in Michigan and New Jersey. Both patients had received multiple courses of vancomycin for methicillin-resistant S. aureus (MRSA) infections.
Another mutation, vancomycin-resistant S. aureus (VRSA) is fully resistant to vancomycin. Patients most at risk for resistant organisms include:
patients with a history of taking vancomycin, third-generation cephalo-sporins, or antibiotics targeted at anaerobic bacteria (such as Clostridium difficile)
patients with indwelling urinary or central venous catheters
elderly patients, especially those with prolonged or repeated hospital admissions
patients with cancer or chronic renal failure
patients undergoing cardiothoracic or intra-abdominal surgery or organ transplants
patients with wounds with an opening to the pelvic or intra-abdominal area, including surgical wounds, burns, and pressure ulcers
patients with enterococcal bacteremia, often associated with endocarditis
patients exposed to contaminated equipment or to a patient with the infecting microbe.