Treatment of Tularemia Caused by Francisella tularensis
Streptomycin is the drug of choice for treating tularemia, with gentamicin being an acceptable alternative when streptomycin is unavailable. For less severe forms, oral doxycycline or ciprofloxacin can be used 1.
First-Line Treatment Options
Severe Tularemia (Pneumonic, Typhoidal, or Critically Ill Patients)
Streptomycin: 1-2 g daily in divided doses for 7-14 days until the patient is afebrile for 5-7 days 2
- Preferred agent with decades of clinical experience
- Dosage: 30 mg/kg/day in 2 divided doses (maximum 2 g daily)
Gentamicin: When streptomycin is unavailable 1
- Dosage: 3-5 mg/kg/day in 3 divided doses for adults
- Dosage for children: 6 mg/kg/day in 3 divided doses
- Adjust dosage according to renal function
Less Severe Forms (Ulceroglandular, Glandular)
Treatment Algorithm Based on Clinical Presentation
Identify clinical form:
- Ulceroglandular (cutaneous ulcer with regional lymphadenopathy)
- Glandular (regional lymphadenopathy without ulcer)
- Oculoglandular (conjunctivitis with preauricular lymphadenopathy)
- Oropharyngeal (stomatitis/pharyngitis with cervical lymphadenopathy)
- Intestinal (abdominal pain, vomiting, diarrhea)
- Pneumonic (primary pleuropulmonary disease)
- Typhoidal (febrile illness without localizing signs)
Assess severity:
- Severe: Pneumonic, typhoidal, or any form with systemic toxicity
- Moderate to mild: Localized disease without systemic toxicity
Select treatment:
- Severe: Start with parenteral aminoglycoside (streptomycin or gentamicin)
- Moderate/mild: Consider oral therapy with doxycycline or ciprofloxacin
Important Clinical Considerations
- Treatment duration: Typically 7-14 days, continuing until patient is afebrile for 5-7 days 2
- Monitoring: Watch for aminoglycoside toxicity (nephrotoxicity, ototoxicity)
- Switching therapy: Consider transitioning from parenteral to oral therapy once clinical improvement occurs
- Relapse risk: Higher with static drugs like tetracyclines or chloramphenicol, especially with shorter courses (< 10 days) 1
Special Populations
- Children: Streptomycin 30 mg/kg/day in 2 divided doses; gentamicin 6 mg/kg/day in 3 divided doses 1
- Adults > 60 years: Consider reduced aminoglycoside dosing due to increased risk of toxicity 2
- Pregnancy: Aminoglycosides preferred over doxycycline or ciprofloxacin
Treatment Pitfalls and Caveats
- F. tularensis is resistant to most β-lactam antibiotics, including ceftriaxone 1
- Laboratory personnel should be notified when tularemia is suspected as the organism poses a significant laboratory hazard 1
- Isolation requires specialized media containing cysteine or other sulfhydryl compounds 1
- Mortality is relatively low (1.4%) with appropriate treatment, but can reach 60% in untreated pneumonic or typhoidal forms 4
- Person-to-person transmission is minimal, so isolation is not typically required 1
Recent evidence suggests fluoroquinolones may be effective, but results have been mixed 1. The most recent guidelines still recommend aminoglycosides as first-line therapy for severe disease, with streptomycin being the preferred agent based on extensive clinical experience 1.
Human Medical Insights AI