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Updated: May 26, 2026
Subcutaneous Infection of Methicillin Resistant Staphylococcus Aureus (MRSA)
Published on: February 9, 2011
A report on the first case of vancomycin-intermediate Staphylococcus aureus (VISA) in Hawai'i
Suttirak Chaiwongkarjohn1, Pornpoj Pramyothin, Nuntra Suwantarat
1Department of Medicine, University of Hawai'i John A. Burns School of Medicine, Honolulu, USA. chsutti@hotmail.com
Abstract:
The state of Hawai'i has the highest prevalence of methicillin-resistant Staphylococcus aureus (MRSA) infection in the United States. Since vancomycin is the most frequently-prescribed antibiotic for healthcare-associated MRSA infection, there is concern for development of vancomycin resistance. We report on a 61 year-old woman with history of previous successful treatments of MRSA bacteremia with vancomycin. She was later hospitalized for catheter-related MRSA bacteremia that persisted despite vancomycin treatment. The vancomycin minimal inhibitory concentration (MIC) was initially 1-2 µg/ml, suggesting susceptibility, but changed to 4 µg/ml. At this level, the organism was classified as a vancomycin-intermediate Staphylococcus aureus (VISA). Therapy was changed from vancomycin to daptomycin, and the patient's blood cultures were sterilized. High suspicion of VISA should be raised in MRSA-infected patients who fail or have a history of vancomycin therapy so that additional susceptibility testing and appropriate antibiotic therapy can be promptly commenced to reduce the morbidity associated with VISA infection.
Insights
Hawaii faces high MRSA rates. A patient developed vancomycin-intermediate Staphylococcus aureus (VISA) despite vancomycin treatment, necessitating a switch to daptomycin for successful infection clearance.
Area of Science:
- Infectious Diseases
- Clinical Microbiology
- Pharmacology
Background:
- Methicillin-resistant Staphylococcus aureus (MRSA) is prevalent in Hawaii.
- Vancomycin is a primary treatment for healthcare-associated MRSA infections.
- Emerging vancomycin resistance in MRSA poses a significant public health threat.
Observation:
- A patient with a history of MRSA bacteremia experienced persistent infection despite vancomycin therapy.
- The patient's MRSA isolate showed a shift in vancomycin minimum inhibitory concentration (MIC) from susceptible to intermediate (4 µg/ml).
- This indicated the development of vancomycin-intermediate Staphylococcus aureus (VISA).
Findings:
- Treatment with vancomycin failed to clear the catheter-related MRSA bacteremia.
- Switching antibiotic therapy to daptomycin successfully sterilized the patient's blood cultures.
- This case highlights the clinical challenge of vancomycin treatment failure due to VISA.
Implications:
- Clinicians should maintain a high index of suspicion for VISA in patients with persistent MRSA infections or a history of vancomycin treatment.
- Prompt susceptibility testing is crucial for identifying VISA.
- Timely escalation of antibiotic therapy, such as to daptomycin, is essential to reduce morbidity and mortality associated with VISA infections.
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