Recommended Treatment for Methicillin-Sensitive Staphylococcus Aureus (MSSA) Coverage

First-Line Treatment Options for Proven MSSA

• The Infectious Diseases Society of America recommends oxacillin, nafcillin, or cefazolin as the preferred first-line treatments for proven MSSA infections due to their superior efficacy and targeted spectrum of activity 1, 2
• Cefazolin is a preferred alternative to antistaphylococcal penicillins, with a dosage of 0.5-1g IV every 8 hours 3
• For less severe infections, cephalexin 500mg PO every 6 hours is an oral option for step-down therapy 3

Empiric Treatment Options When MSSA is Suspected

• The Infectious Diseases Society of America recommends piperacillin-tazobactam 4.5g IV every 6 hours, cefepime 2g IV every 8 hours, levofloxacin 750mg IV daily, imipenem 500mg IV every 6 hours, or meropenem 1g IV every 8 hours for empiric treatment of MSSA 4, 5

Clinical Considerations

• For osteomyelitis, 4-6 weeks of therapy is required, and rifampin may be added for biofilm penetration 6
• For skin and soft tissue infections, shorter courses of 7-14 days may be adequate 3

Special Considerations

• For patients with severe penicillin allergy, vancomycin or clindamycin may be considered 4, 3

Duration of Therapy

• For endocarditis, 4-6 weeks of therapy is recommended 6
• For osteomyelitis, 4-6 weeks of therapy is recommended 6

Common Pitfalls to Avoid

• Failure to transition from empiric to targeted therapy once MSSA is confirmed can be avoided by monitoring and adjusting treatment accordingly 4, 2
• Inadequate surgical debridement when indicated, particularly for abscesses, osteomyelitis, or necrotizing infections, can be avoided by considering surgical intervention 3, 6