Sandbox:omtx

Antimicrobial Regimens

Hematogenous Osteomyelitis

• 1. Empiric antimicrobial therapy

• 1.1 Adult (>21 yrs)

• 1.1.1 MRSA possible

• Preferred regimen: Vancomycin 1 g IV q12h (if over 100 kg, 1.5 g IV q12h)

• 1.1.2 MRSA unlikely

• Preferred regimen: Nafcillin 2 g IV q4h OR Oxacillin 2 g IV q4h

• 1.2 Children (>4 months)

• 1.2.1 MRSA possible

• Preferred regimen: Vancomycin 40 mg/kg/day IV q6–8h

• 1.2.2 MRSA unlikely

• Preferred regimen: Nafcillin 37 mg/kg IV q6h (maximum dose 8–12 g/day) OR Oxacillin 37 mg/kg IV q6h (maximum dose 8–12 g/day)

• Note: Add Ceftazidime 50 mg/kg IV q8h or Cefepime 150 mg/kg/day IV q8h if Gram-negative bacilli on Gram stain.

• 2. Pathogen-directed antimicrobial therapy

• 2.1 MSSA

• Preferred regimen: Nafcillin 2 g IV q4h OR Oxacillin 2 g IV q4h OR Cefazolin 2 g IV q8h
• Alternative regimen: Vancomycin 1 g IV q12h (if over 100 kg, 1.5 g IV q12h)

• 2.2 MRSA

• Preferred regimen: Vancomycin 1 g IV q12h
• Alternative regimen: Linezolid 600 mg q12h IV/PO ± Rifampin 300 mg po/IV bid

Contiguous Osteomyelitis with Vascular Insufficiency

• Osteomyelitis, contiguous with vascular insufficiency

• Debride overlying ulcer and send bone specimen for histology and culture.
• No empiric antimicrobial therapy unless acutely ill.
• Antibiotic therapy should be based on culture results
• Treatment duration is at least 6 weeks.
• Revascularize if possible.

Open Fracture Osteomyelitis

• Long bone, post-internal fixation of fracture

• 1. S. aureus or P. aeruginosa

• Preferred regimen: Vancomycin 1 g IV q12h AND (Ceftazidime 2 g IV q8h OR Cefepime 2 g IV q8h)
• Alternative regimen (1): Linezolid 600 mg IV/PO bid AND Ceftazidime 2 g IV q8h
• Alternative regimen (2): Linezolid 600 mg IV/PO bid AND Cefepime 2 g IV q8h

• 2. Gram negative bacilli

• Preferred regimen (1): Ciprofloxacin 750 mg PO bid
• Preferred regimen (2): Levofloxacin 750 mg PO qd

Diabetic Foot Osteomyelitis

• 1. Chronic infection or recent antibiotic use

• Preferred regimen (1): Levofloxacin 750 mg IV/PO q24h
• Preferred regimen (2): Cefoxitin 1 g IV q4h (or 2 g IV q6–8h)
• Preferred regimen (3): Ceftriaxone 1–2 g/day IV/IM q12–24h
• Preferred regimen (4): Ampicillin-Sulbactam 1.5–3 g IV/IM q6h
• Preferred regimen (5): Moxifloxacin 400 mg IV/PO q24h
• Preferred regimen (6): Ertapenem 1 g IV/IM q24h
• Preferred regimen (7): Tigecycline 100 mg IV THEN 50 mg IV q12h (active against MRSA)
• Preferred regimen (8): Imipenem-Cilastatin 0.5–1 g IV q6–8h (Not active against MRSA)
• Alternative regimen (1): Levofloxacin 750 mg IV/PO q24h AND Clindamycin 150–300 mg PO qid
• Alternative regimen (2): Ciprofloxacin 600–1200 mg/day IV q6–12h AND Clindamycin 150–300 mg PO qid
• Alternative regimen (3): Ciprofloxacin 1200–2700 mg IV q6–12h AND Clindamycin 150–300 mg PO qid (for more severe cases)

• 2. High risk for MRSA

• Preferred regimen (1): Linezolid 600 mg IV/PO q12h
• Preferred regimen (2): Daptomycin 4 mg/kg IV q24h
• Preferred regimen (3): Vancomycin 15–20 mg/kg IV q8–12h (trough: 10–20 mg/L)

• 3. High risk for Pseudomonas aeruginosa

• Preferred regimen: Piperacillin–Tazobactam 3.375 g IV q6–8h

• 4. Polymicrobial infection

• Preferred regimen: (Vancomycin 15–20 mg/kg IV q8–12h (trough: 10–20 mg/L) OR Linezolid 600 mg IV/PO q12h OR Daptomycin 4 mg/kg IV q24h) AND (Piperacillin–Tazobactam 3.375 g IV q6–8h OR Imipenem–Cilastatin 0.5–1 g IV q6–8h OR Ertapenem 1 g IV/IM q24h OR Meropenem 1 g IV q8h)
• Alternative regimen: (Vancomycin 15–20 mg/kg IV q8–12h (trough: 10–20 mg/L) OR Linezolid 600 mg IV/PO q12h OR Daptomycin 4 mg/kg IV q24h) AND (Ceftazidime 2 g IV q8h OR Cefepime 2 g IV q8h OR Aztreonam 2 g IV q6–8h) AND Metronidazole 15 mg/kg IV, then 7.5 mg/kg IV q6h