Which methicillin‑resistant Staphylococcus aureus (MRSA) infection is more likely to recur: one at a previously infected skin or soft‑tissue site versus a postoperative MRSA surgical‑site infection without prior colonization?

MRSA Recurrence Risk: Previously Infected Site vs. Postoperative Surgical Site

MRSA infections at previously infected skin and soft tissue sites are more likely to recur than postoperative MRSA surgical site infections, primarily because persistent colonization drives recurrence in community-acquired infections, whereas surgical site infections typically result from transient perioperative contamination.

Key Evidence on Recurrence Patterns

Community-Acquired MRSA at Previously Infected Sites

Persistent colonization is the primary driver of recurrent MRSA skin and soft tissue infections. Among military trainees with MRSA SSTI, genomic analysis revealed that infection and colonization isolates showed minimal genetic variation (median 17 single nucleotide variants), indicating that persistent colonization from a single acquisition event accounts for both initial infection and recurrence 1.

• Recurrence rates are substantial: 53% of index patients with community-acquired MRSA SSTI experienced interval recurrent infections within 12 months 2
• Individuals persistently colonized with MRSA had 1.56 times higher odds of developing recurrent SSTI compared to those without persistent colonization 2
• Environmental contamination perpetuates the cycle: increasing strain-specific environmental contamination pressure was associated with persistent individual colonization (OR 1.17) 2
• The nares are the most common reservoir, with colonization often persisting despite treatment 1, 2

Postoperative MRSA Surgical Site Infections

Postoperative MRSA infections following elective surgery show lower recurrence rates, even in previously colonized patients who undergo successful eradication therapy. Among 90 MRSA-colonized patients who underwent elective orthopedic surgery after successful eradication, only 6.7% developed surgical site infections within one year 3.

• The progression from colonization to infection in surgical patients occurs primarily in high-risk scenarios: intensive care settings, presence of surgical wounds, pressure ulcers, and intravenous catheterization 4
• Surgical site infections represent a different pathophysiology: they typically result from perioperative contamination rather than persistent endogenous colonization 5
• Clean surgical procedures have lower baseline infection rates, with S. aureus from exogenous environment or transient skin flora being the usual cause 5

Clinical Implications and Risk Stratification

High-Risk Features for Recurrence at Previously Infected Sites

Prior MRSA infection or colonization within the past year is the single most reliable predictor of future MRSA infection 6, 7. Additional risk factors include:

• Persistent household environmental contamination with the same MRSA strain 2
• Household contacts who are colonized (25.7% of SSTI patients had concurrent colonization) 1
• History of previous SSTI (OR 2.55 for recurrent infection) 2
• Failure to address underlying predisposing factors such as lymphedema, venous insufficiency, or skin breakdown 5

Lower Risk Profile for Postoperative Infections

• Successful preoperative MRSA eradication significantly reduces but does not eliminate risk 3
• Lower limb joint replacement carries higher risk (4.4% deep infection rate) even after eradication 3
• Most surgical site infections occur from perioperative factors rather than persistent colonization 5

Prevention Strategies

For Recurrent Community-Acquired MRSA SSTI

Prophylactic antibiotics should be considered for patients with 3-4 episodes per year despite treating predisposing factors 5. Options include:

• Oral penicillin or erythromycin twice daily for 4-52 weeks 5
• Intramuscular benzathine penicillin every 2-4 weeks 5
• Continue prophylaxis as long as predisposing factors persist 5

Address underlying conditions aggressively: treat edema, obesity, eczema, venous insufficiency, and toe web abnormalities 5. Intranasal mupirocin application reduces persistent colonization (OR 0.44) 2.

For Postoperative Infections

• Appropriate perioperative antibiotic prophylaxis based on procedure type 5
• No evidence supports extended postoperative prophylaxis 5
• Screen and eradicate MRSA colonization preoperatively in high-risk patients 3

Common Pitfalls

Do not assume successful treatment of one MRSA SSTI prevents recurrence—the underlying colonization often persists despite clinical cure 1, 2. Environmental decontamination must accompany personal decolonization efforts 2.

Do not overlook household transmission dynamics—19% of household contacts developed interval SSTIs, indicating the importance of household-level interventions 2.

For surgical patients, do not rely solely on eradication therapy—previously colonized patients remain at elevated risk even after successful decolonization, particularly for lower limb joint replacements 3.