What is the treatment for a Staph (Staphylococcus) infection?

Treatment of Staphylococcus Infections

For Staphylococcus infections, treatment should be tailored based on the type of infection, severity, and suspected methicillin resistance status, with empiric therapy typically including anti-staphylococcal antibiotics such as trimethoprim-sulfamethoxazole, doxycycline, or vancomycin for more severe cases.

Classification of Staphylococcal Infections

Treatment varies based on:

• Infection site (skin/soft tissue, bloodstream, bone, etc.)
• Severity (uncomplicated vs. complicated)
• Suspected resistance pattern (MSSA vs. MRSA)
• Outpatient vs. inpatient management

Empiric Treatment Algorithm

Uncomplicated Skin and Soft Tissue Infections

• Simple abscesses or boils: Incision and drainage is the primary treatment 1
• Outpatient SSTI treatment options:
  • Trimethoprim-sulfamethoxazole (TMP-SMX) 160-320/800-1600 mg PO q12h
  • Doxycycline 100 mg PO q12h
  • Minocycline 200 mg loading dose, then 100 mg PO q12h
  • Clindamycin (if susceptible) 1, 2
• Duration: 5-10 days 1, 2

Complicated Skin and Soft Tissue Infections

• Inpatient SSTI treatment options:
  • Vancomycin 30-60 mg/kg/day IV in 2-4 divided doses
  • Teicoplanin 6-12 mg/kg/dose IV q12h (three doses), then daily
  • Linezolid 600 mg IV/PO q12h
  • Daptomycin 4 mg/kg/dose IV daily 1, 3
• Duration: 7-14 days 1, 2

Bacteremia and Invasive Infections

• Uncomplicated bacteremia:
  • Vancomycin 30-60 mg/kg/day IV in 2-4 divided doses
  • Duration: 2 weeks 1
• Complicated bacteremia:
  • Vancomycin 30-60 mg/kg/day IV in 2-4 divided doses
  • Daptomycin 6-10 mg/kg/dose IV daily
  • Duration: 4-6 weeks 1
• Infective endocarditis:
  • Native valve: Vancomycin 30-60 mg/kg/day IV in 2-4 divided doses
  • Prosthetic valve: Add rifampin and gentamicin
  • Duration: 4-6 weeks 1

Treatment Based on Methicillin Resistance

Methicillin-Susceptible S. aureus (MSSA)

• First-line: Penicillinase-resistant penicillins (flucloxacillin, cloxacillin, oxacillin, nafcillin) 4, 5
• Alternatives: First-generation cephalosporins, beta-lactam/beta-lactamase inhibitor combinations 5

Methicillin-Resistant S. aureus (MRSA)

• Community-acquired MRSA:
  • Often susceptible to TMP-SMX, doxycycline, clindamycin 6, 4
  • Caution with clindamycin due to potential for inducible resistance 6
• Hospital-acquired MRSA:
  • Vancomycin remains the reference standard for serious infections 6
  • Alternatives: linezolid, daptomycin, teicoplanin 6, 4

Special Considerations

Biofilm-Associated Infections (e.g., Implant-Related)

• Rifampicin is the agent of choice for staphylococcal biofilm infections 1
• Must be combined with another antibiotic (fluoroquinolone preferred) to prevent resistance 1
• For implant retention: 12 weeks of antibiotics
• After implant removal: 6 weeks of antibiotics 1

Pediatric Considerations

• Similar antibiotics as adults with age-appropriate dosing
• Doxycycline not recommended for children under 8 years 2, 7
• For severe infections in children: vancomycin, clindamycin, or linezolid 7

Monitoring and Follow-up

• Monitor for clinical response within 48-72 hours
• Adjust therapy based on culture results
• For vancomycin, monitor trough levels (target 10-20 μg/mL) 2
• Follow-up for at least 12 months after cessation of therapy for invasive infections 1

Common Pitfalls to Avoid

• Failing to obtain appropriate cultures before starting antibiotics
• Using clindamycin without checking for inducible resistance
• Starting rifampicin before adequate surgical debridement or when wounds are not dry
• Using fluoroquinolone monotherapy for staphylococcal infections due to rapid resistance development
• Inadequate duration of therapy, especially for biofilm-associated or invasive infections
• Neglecting source control (drainage of abscesses, removal of infected devices) 2

By following this structured approach to treating staphylococcal infections, clinicians can optimize outcomes while minimizing complications and the development of antimicrobial resistance.