MRSA Bone & Joint Infections

Osteomyelitis

• Surgical debridement and drainage of associated softtissue abscesses is the mainstay of therapy and should be performed whenever feasible
• For choice of antibiotics, refer the table below
• optimal duration of therapy for MRSA osteomyelitis is unknown.
• A minimum 8-week course is recommended
• Some experts suggest an additional 1-3 months (and possibly longer for chronic infection or if debridement is not performed) of oral rifampin-based combination therapy with TMP-SMX, doxycycline/minocycline, clindamycin, or a fluoroquinolone, chosen on the basis of susceptibilities

Septic Arthritis

• Drainage or debridement of the joint space should always be performed
• refer to antibiotic choices for osteomyelitis
• A 3-4-week course of therapy is suggested

Pediatric

• For children with acute hematogenous MRSA osteomyelitis and septic arthritis, IV vancomycin is recommended
• If the patient is stable without ongoing bacteremia or intravascular infection, clindamycin 10–13 mg/kg/dose IV every 6–8 h (to administer 40 mg/kg/day) can be used as empirical therapy if the clindamycin resistance rate is low with transition to oral therapy if the strain is susceptible
• The exact duration of therapy should be individualized, but typically a minimum 3–4-week course is recommended for septic arthritis and a 4–6-week course is recommended for osteomyelitis.

Antibiotic Considerations

• Despite concerns about poor bone penetration and relative inefficacy in animal models, vancomycin remains the primary treatment of MRSA osteomyelitis
• Failure rates of up to 35%–46% have been reported
• These unsatisfactory responses to vancomycin have led some experts to recommend the addition of rifampin because of its excellent penetration into bone and biofilm
• For patients with concurrent bacteremia, rifampin should be added to the treatment regimen after clearance of bacteremia.
• Clindamycin achieves good bone concentrations and is highly effective for treatment of non–critically ill children with MRSA osteomyelitis

References:

1. Clinical Practice Guidelines by the Infectious Diseases Society of America for the Treatment of Methicillin-Resistant Staphylococcus Aureus Infections in Adults and Children. Clinical Infectious Diseases 2011;1–38
2. National Antibiotic Guideline 2014