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Updated: Jul 6, 2026
Subcutaneous Infection of Methicillin Resistant Staphylococcus Aureus (MRSA)
Published on: February 9, 2011
Community-acquired methicillin-resistant Staphylococcus aureus emerging as an important cause of necrotizing
1Department of Medicine, Division of Infectious Diseases, University of Colorado Health Sciences Center, Denver, Colorado., USA. Young.Lisa@yahoo.com
Background:
Necrotizing fasciitis (NF) is an uncommon fulminant soft tissue infection characterized by extensive fascial necrosis. Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) isolates producing the Panton-Valentine leukocidin (PVL) cytotoxin have been associated with serious necrotizing infections, but NF caused by CA-MRSA has been described only recently. We reviewed our NF experience at Denver Health Medical Center, where CA-MRSA accounts for more than 50% of community S. aureus clinical isolates.
Methods:
Patients treated for NF from January 2004 to February 2006 were identified by review of pathology records and diagnostic codes, and their medical records were reviewed. Isolates of MRSA from monomicrobial NF underwent testing for the PVL gene and pulsed-field gel electrophoresis to determine relatedness to CA-MRSA strains.
Results:
Five of 30 NF cases during the study period, all involving the extremities, were caused by MRSA. Monomicrobial MRSA NF accounted for three cases, with all of the patients reporting a distinct "spider bite" lesion 2-3 days prior to admission. The median age was 32 years (range 28-55 years). Resistance to erythromycin and levofloxacin was present in four isolates. None of the isolates displayed inducible clindamycin resistance. Within 12 hours of admission, all patients received empiric antibiotics to which their isolate was susceptible. Patients required a median of six surgical procedures (range 2-7 operations). All patients survived. The MRSA isolates tested positive for PVL and had the USA 300 CA-MRSA deoxyribonucleic acid banding pattern.
Conclusions:
Community-acquired MRSA is an important cause of NF in our region, accounting for > 15% of NF cases. This infection was associated with significant morbidity necessitating multiple surgical interventions. Given the propensity of PVL-positive CA-MRSA to cause severe necrotizing infections, it is reasonable to administer empiric MRSA coverage for NF in endemic locations.
Insights
Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is a significant cause of necrotizing fasciitis (NF), a severe soft tissue infection. Early empiric MRSA coverage is recommended in endemic areas due to its aggressive nature.
Area of Science:
- Infectious Diseases
- Microbiology
- Dermatology
Background:
- Necrotizing fasciitis (NF) is a rare, aggressive soft tissue infection.
- Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) producing Panton-Valentine leukocidin (PVL) is increasingly linked to severe infections.
- CA-MRSA is a prevalent cause of S. aureus isolates in certain regions.
Observation:
- A review of NF cases at Denver Health Medical Center identified MRSA as the causative agent in 5 out of 30 cases.
- Three monomicrobial MRSA NF cases presented with a preceding "spider bite" lesion.
- Affected patients were relatively young (median age 32) and required extensive surgical intervention (median 6 procedures).
Findings:
- All identified MRSA isolates were PVL-positive and matched the USA 300 CA-MRSA strain.
- The MRSA strains showed resistance to erythromycin and levofloxacin but not clindamycin.
- Despite the severity, all patients survived and received effective empiric antibiotic treatment.
Implications:
- CA-MRSA is a notable cause of NF, accounting for over 15% of cases in the studied region.
- The high morbidity associated with MRSA-induced NF underscores the need for prompt diagnosis and treatment.
- Empiric antibiotic coverage for MRSA in suspected NF cases is advisable in areas where CA-MRSA is endemic.
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