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Updated: Jun 13, 2025
Subcutaneous Infection of Methicillin Resistant Staphylococcus Aureus MRSA
Published on: February 9, 2011
Methicillin-resistant Staphylococcus aureus in diabetic and non-diabetic foot infections
Lawrence A Lavery1,2, Mario C Reyes1, Mehmet Suludere1
1Department of Plastic Surgery, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Abstract:
To identify the incidence of methicillin-resistant Staphylococcus aureus (MRSA) infection, reinfection and clinical outcomes. Four hundred forty-six patients that were admitted to the hospital with moderate or severe foot infections were retrospectively reviewed. Tissue and bone cultures were obtained from the index hospital admission. Conversion was defined as methicillin susceptible Staphylococcus aureus in the first culture and subsequently MRSA when there was a reinfection. The incidence of MRSA was 7.8% (n = 35), with no significant difference between soft tissue infections (7.7%) and osteomyelitis (8.0%). MRSA incidence was 9.4 times higher in non-diabetics (23.8% vs. 3.2%, p = <0.01). The incidence of reinfection was 40.8% (n = 182). Conversion to MRSA was seen in 2.2% (n = 4) total, occurring in 5.4%. Non-diabetics were 20.1 times more likely to have MRSA reinfection than people with diabetes (28.6% vs. 1.9%, p < 0.001). MRSA patients had a higher proportion of healed wounds (82.4% vs. 69.3%, p = 0.02). There were no differences in other clinical outcomes in MRSA vs. other infections in reinfection (28.6% vs. 24.3%, p = 0.11), amputation (48.6% vs. 52.0%, p = 0.69) or hospitalization (28.6% vs. 42.6, p = 0.11). The incidence of MRSA for the first infection (7.8%), reinfection (6.0%) and conversion to MRSA (2.2%) was low. MRSA was 9.4 times more common in people without diabetes.
Insights
Methicillin-resistant Staphylococcus aureus (MRSA) infections are uncommon in foot infections, with a low incidence of reinfection. Non-diabetic patients face a significantly higher risk of MRSA infection and reinfection compared to diabetic patients.
Area of Science:
- Infectious Diseases
- Microbiology
- Clinical Medicine
Background:
- Methicillin-resistant Staphylococcus aureus (MRSA) is a significant pathogen causing hospital-acquired infections.
- Foot infections, particularly in moderate to severe cases, require careful microbiological assessment.
- Understanding MRSA incidence and outcomes is crucial for effective patient management.
Purpose of the Study:
- To determine the incidence of MRSA infections, reinfections, and conversions in patients with moderate to severe foot infections.
- To compare clinical outcomes between MRSA and other bacterial infections in this patient cohort.
- To identify risk factors associated with MRSA infection and reinfection.
Main Methods:
- Retrospective review of 446 patients admitted with moderate or severe foot infections.
- Analysis of tissue and bone cultures obtained during the index hospital admission.
- Definition of conversion as a shift from methicillin-susceptible Staphylococcus aureus to MRSA in subsequent cultures.
Main Results:
- The overall incidence of MRSA was 7.8%, with similar rates in soft tissue infections (7.7%) and osteomyelitis (8.0%).
- MRSA incidence was significantly higher in non-diabetic patients (23.8%) compared to diabetic patients (3.2%).
- Reinfection occurred in 40.8% of patients, with a 2.2% conversion rate to MRSA. Non-diabetics had a substantially higher risk of MRSA reinfection (28.6% vs. 1.9%).
- MRSA patients showed a higher proportion of healed wounds (82.4%) compared to other infections (69.3%). No significant differences were observed in other clinical outcomes like amputation or hospitalization rates.
Conclusions:
- The incidence of MRSA, reinfection, and conversion to MRSA in moderate to severe foot infections is relatively low.
- Non-diabetic status is a significant risk factor for both initial MRSA infection and subsequent reinfection.
- While MRSA infections were associated with better wound healing rates, further research may be needed to elucidate all clinical implications.
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