Osteomyelitis — Empiric Antibiotic Recommendations — Clinical Pathway: Emergency and Inpatient

Osteomyelitis Clinical Pathway — Emergency Department and Inpatient

Empiric Antibiotic Therapy for Osteomyelitis

General Principles

  • Culture-negative osteomyelitis is common (up to 50% of cases), so monitor response closely.
  • If increasing pain, persistently elevated inflammatory markers, or worsening fever curve after 48 hours of preferred first-line therapy, consider treatment failure.

Most children require 4 weeks of therapy. Conversion to oral therapy occurs after demonstrable clinical improvement.

Target Pathogens Uncommon Pathogens
  • Staphylococcus aureus (MSSA and MRSA) – all ages
  • Streptococcus pyogenes (group A Streptococcus) – all ages
  • Kingella kingae:
    • Generally occurs in children age 6 months through 4 years
    • Unusual predilection for small bones, including small bones of feet
    • Causes spondylodiskitis and pyogenic arthritis
    • Clinical manifestations similar to other bacterial pathogens, but subacute course may be common
    • Preceding history of URI symptoms may be reported
  • Streptococcus pneumoniae
  • Salmonella species
  • Haemophilus influenzae type b
  • Brucella
  • Note: The above pathogens are not common causes of osteomyelitis; however, some factors, such as incomplete immunization, exposure history (e.g., contact with reptiles), and underlying conditions, may necessitate coverage of these pathogens in consultation with Infectious Diseases.

Empiric Antibiotic Recommendations for Osteomyelitis

Indication First-Line Therapy Allergy to First-Line β-Lactam
Assess Need for Alternative
No MRSA risk factors
  • Cefazolin, IV
    • 35 mg/kg/dose every 8 hours
    • Max: 2,000 mg/dose
  • Clindamycin, IV
    • 14 mg/kg/dose every 8 hours
    • Max: 900 mg/dose
    • Please confirm clindamycin susceptibility if prior cultures are available; if prior history of clindamycin-resistant MRSA, discuss empiric therapy with Infectious Diseases
  • MRSA risk factors:
    • History of MRSA infection or carriage
    • Known close/household contact with MRSA and/or recurrent skin abscesses
    • Use of IV drugs
  • Clindamycin, IV
    • 14 mg/kg/dose every 8 hours
    • Max: 900 mg/dose
    • Please confirm clindamycin susceptibility if prior cultures are available; if prior history of clindamycin-resistant MRSA, discuss empiric therapy with Infectious Diseases
    • If concern for Kingella kingae in a patient with MRSA risk factors, add cefazolin:
    • Cefazolin, IV
    • 35 mg/kg/dose every 8 hours
    • Max: 2,000 mg/dose
 Discuss empiric therapy with Infectious Diseases
Osteomyelitis with gram-positive bacteremia (susceptibilities pending)
  • Vancomycin, IV
    • Infants, children and adolescents ≤ 50 kg:
    • 15 mg/kg/dose IV every 6 hours
    • Max: 750 mg/dose
    • Children and adolescents > 50 kg and adults:
    • 15 mg/kg/dose IV every 8 hours
    • Max: 1,000 mg/dose
 Discuss empiric therapy with Infectious Diseases

CHOP Formulary for complete drug information.