Francisella tularensis

Francisella tularensis

Background:
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Other   (Gram Negative Bacilli)  
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>Aeromonas species:
     1] Aeromonas hydrophila
     2] Aeromonas veronii
     3] Aeromonas shubertii
>Bartonella species:
     1] Bartonella bacilliformis
     2] Bartonella henselae (organism responsible for cat scratch disease)
     3] Bartonella Quintana
     4] Other
>Campylobacter:
     1] Campylobacter fetus
     2] Campylobacter jejuni
>Capnocytophaga species:
     1] Capnocytophaga canimorsus
     2] Capnocytophaga ochracea
>Francisella tularensis Led
>Helicobacter pylori
>Legionella species: ( L. pneumophila)
>Plesiomonas shigelloides
>Vibrio species:
     1] Vibrio cholera
     2] Vibrio parahaemolyticus
     3] Vibrio damsela
     4] Other

Francisella tularensis: 

  • Pathogenic species of Gram-negative bacteria and the causative agent of tularemia.
  • Fastidious, facultative intracellular bacterium which requires cysteine for growth.
  • Due to its low infectious dose, ease of spread by aerosol and high virulence, F. tularensis is classified as a Class A Select Agent by the U.S. government, along with other potential agents of bioterrorism such as Yersinia pestis, Smallpox and Ebola.

 

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Therapy:
Important considerations:  The choice of an agent should be based on local antimicrobial sensitivities, site of infection, cost, and comorbid conditions.   Generally, the most common agents/regimens are listed first.  Listed dosages may need to be adjusted for renal dysfunction.  

  1. Streptomycin 0.5 – 1 gram IM q12h x 10 days (Maximum: 2 grams/day)
  2. Gentamicin 5 mg/kg/day IV x 10 days – Adjust regimen based on estimated clearance.
  3. Doxycycline 100mg IV/oral twice daily
  4. Ciprofloxacin 750 mg orally q12h or 400mg IV q12h
  5. Severe disease e.g. meningitis: 
    • [Gentamicin 5 mg/kg/day IV x 10 days – Adjust regimen based on estimated clearance  OR Streptomycin 0.5 – 1 gram IM q12h x 10 days ]
    • PLUS 
    • [Chloramphenicol 50-100 mg/kg/day IV in divided doses every 6 hours (Maximum daily dose is 4 grams e.g. 1 gram q6h)   OR   Doxycycline 100mg IV  twice daily] 

Francisella tularensis