Vancomycin intermediate-resistant Staphylococcus aureus.

OBJECTIVE

To describe further details about the third reported case of vancomycin intermediate-resistant Staphylococcus aureus (VISA).

CASE SUMMARY

A patient with a history of recurrent methicillin-resistant S. aureus (MRSA) bacteremia was treated with several courses of vancomycin for 18 of 23 possible weeks on an inpatient/outpatient basis. After 6 months of repeated courses, an isolate of MRSA showed a minimum inhibitory concentration of 8 micrograms/mL, indicating intermediate resistance to vancomycin. The patient continued to receive a vancomycin/aminoglycoside/rifampin regimen and, when he was hospitalized several weeks later, no further MRSA or VISA was detected.

DISCUSSION

Prolonged, intermittent vancomycin use (18 of 23 possible weeks) for MRSA bacteremia on an inpatient/outpatient basis most likely contributed to the development of VISA. Infection control measures prevented the spread of VISA among patients and healthcare workers.

CONCLUSIONS

Infection control measures and evaluation of antimicrobial prescribing need to be strongly enforced to further prevent the spread and development of resistant organisms.