What is the best treatment approach for a suspected Methicillin-resistant Staphylococcus aureus (MRSA) abscess?

Treatment of Suspected MRSA Abscess

Incision and drainage is the cornerstone of treatment for MRSA abscesses and should be performed whenever feasible, with antibiotics serving as adjunctive therapy rather than primary treatment. 1

Initial Management Approach

Surgical Intervention

• Drainage is mandatory - surgical debridement and drainage of the abscess is the mainstay of therapy and must be performed before or concurrent with antibiotic initiation 1
• Obtain cultures from purulent drainage before starting antibiotics to confirm MRSA and guide definitive therapy 1
• For simple, small abscesses (<5 cm) without systemic symptoms, incision and drainage alone may be adequate without antibiotics 1

When to Add Antibiotics

Antibiotics are indicated for 2:

• Severe or extensive local infection
• Signs of systemic illness (fever, tachycardia, hypotension)
• Multiple abscesses
• Immunocompromised patients
• Failed drainage alone
• Surrounding cellulitis

Antibiotic Selection

Outpatient Oral Options (Non-Severe Infections)

First-line choices 2, 1:

• Trimethoprim-sulfamethoxazole (TMP-SMX): 1-2 double-strength tablets (160/800 mg) orally twice daily 2, 1
• Doxycycline or minocycline: 100 mg orally twice daily 2, 1
• Clindamycin: 300-450 mg orally three times daily - only if local resistance rates are <10% 2, 1
• Linezolid: 600 mg orally twice daily (reserve for more severe cases or intolerance to other agents) 2, 3

Critical caveat: Clindamycin resistance in MRSA can exceed 10-20% in many communities, making TMP-SMX or doxycycline safer empiric choices 2

Inpatient IV Options (Complicated/Severe Infections)

For hospitalized patients with complicated skin infections, deeper infections, or systemic toxicity 2, 1:

• Vancomycin: 15-20 mg/kg IV every 8-12 hours (target trough 15-20 mcg/mL for serious infections) 2, 4
• Daptomycin: 4-6 mg/kg IV once daily 2, 1
• Linezolid: 600 mg IV twice daily 2, 3
• Telavancin: 10 mg/kg IV once daily 2

Linezolid may be superior to vancomycin for MRSA skin and soft tissue infections based on recent network meta-analysis showing improved clinical success rates (RR 1.71; 95%-CI 1.45-2.02), though it has higher adverse reaction rates 5

Treatment Duration

• Uncomplicated abscesses with adequate drainage: 5-10 days 2, 1
• Complicated skin and soft tissue infections: 7-14 days 2, 1
• Duration should be guided by clinical response - resolution of fever, decreasing erythema, and healing of wound 2

Special Populations

Pediatric Patients

• Vancomycin is the recommended IV agent 2, 1
• Clindamycin 10-13 mg/kg/dose IV every 6-8 hours can be used if patient is stable without bacteremia and local resistance is <10% 2
• Avoid tetracyclines in children <8 years of age 2, 1
• Mupirocin 2% topical ointment for minor superficial infections 2

If Concurrent Bacteremia Suspected

• Obtain blood cultures before antibiotics 1
• Minimum 2 weeks for uncomplicated bacteremia, 4-6 weeks for complicated bacteremia 1
• Repeat blood cultures 2-4 days after initial positive cultures to document clearance 1

Critical Pitfalls to Avoid

• Never rely on beta-lactam antibiotics alone (cephalexin, dicloxacillin) for suspected MRSA - they are completely ineffective 1
• Failure to drain the abscess will lead to treatment failure regardless of antibiotic choice 1
• Do not use rifampin as monotherapy or adjunctive therapy for skin infections 2, 1
• Check local antibiogram before using clindamycin empirically - resistance rates vary widely by region 2

Prevention of Recurrence

For patients with recurrent MRSA abscesses 2, 1:

• Keep draining wounds covered with clean, dry bandages 2, 1
• Regular handwashing with soap and water or alcohol-based gel 2, 1
• Avoid sharing personal items (razors, towels, linens) 2
• Consider decolonization with intranasal mupirocin and chlorhexidine body washes after treating active infection 1
• Evaluate and potentially treat household contacts if recurrent infections persist 2