What are the empiric antibiotics for Osteomyelitis (infection of the bone)?

From the Guidelines

Empiric antibiotic therapy for osteomyelitis should include coverage for Staphylococcus aureus, and a 6-week course of antibiotics is adequate for the treatment of osteomyelitis in the absence of implanted foreign bodies and surgical debridement, as supported by the most recent study 1.

Key Considerations

• The optimal route of administration of antibiotic therapy has not been established, and parenteral, oral, or initial parenteral therapy followed by oral therapy may be used depending on individual patient circumstances 1.
• Antibiotics available for parenteral administration include IV vancomycin and daptomycin, with some options having both parenteral and oral routes of administration, such as TMP-SMX, linezolid, and clindamycin 1.
• Surgical debridement and drainage of associated soft-tissue abscesses is the mainstay of therapy and should be performed whenever feasible 1.

Treatment Duration and Monitoring

• Treatment duration typically ranges from 4-6 weeks, with the first 2 weeks often administered intravenously followed by oral therapy if a suitable option exists with good bioavailability.
• Monitoring for treatment response includes tracking inflammatory markers like C-reactive protein and erythrocyte sedimentation rate, which should decline with effective treatment 1.

Specific Patient Populations

• For patients with diabetic foot osteomyelitis, 6 weeks of antibiotic therapy is recommended, and surgical debridement or resection of infected bone may be necessary in some cases 1.
• For patients with concurrent bacteremia, rifampin should be added after clearance of bacteremia 1.

From the Research

Osteomyelitis Empiric Antibiotics

• The selection of empiric antibiotics for osteomyelitis is critical and should be based on the suspected causative pathogen and its antimicrobial susceptibility profile 2.
• For methicillin-susceptible Staphylococcus aureus, intravenous beta-lactams are the treatment of choice, while vancomycin is the treatment of choice for methicillin-resistant Staphylococcus aureus osteomyelitis 3.
• Oral fluoroquinolones and parenteral beta-lactam agents can be used for the treatment of gram-negative osteomyelitis, but increasing resistance has complicated management of these infections 3.
• The combination of vancomycin with a broad-spectrum cephalosporin or fluoroquinolone may be appropriate for empiric treatment of hematogenous vertebral osteomyelitis 2.
• Bone-targeted vancomycin formulations, such as BT2-peg2-vancomycin, may have increased antimicrobial activity compared to conventional vancomycin in the treatment of MRSA osteomyelitis 4.

Antibiotic Regimens

• Levofloxacin plus rifampicin, levofloxacin plus clindamycin, and amoxicillin-clavulanate plus ciprofloxacin are oral combinations that may be effective for the treatment of osteomyelitis, but their susceptibility rates vary depending on the causative pathogen and the setting (community-acquired or healthcare-associated) 2.
• Vancomycin combined with ciprofloxacin, ceftriaxone, ceftazidime, or cefepime is a suitable empiric regimen for the treatment of osteomyelitis, with high susceptibility rates 2.

Treatment Considerations

• The optimal duration of antibiotic treatment for osteomyelitis remains controversial, and recommendations are often based on expert opinion, case series, and extrapolations from animal models 3, 5.
• The emergence of multi-drug resistant organisms poses major therapeutic challenges in the treatment of osteomyelitis, and identification of the causative agent and subsequent targeted antibiotic treatment is crucial for a successful outcome 5, 2.