Francisella tularensis (F. tularensis)

Francisella tularensis is a highly infectious, Gram-negative, facultative intracellular bacterium that serves as the causative agent of tularemia, a zoonotic disease also known as rabbit fever (Maurin, 2015). It is notable for its extreme virulence and an exceptionally low infectious dose, where as few as 10 organisms can initiate a potentially fatal infection in humans (Sjöstedt, 2007; Baylor College of Medicine). Due to its high infectivity and potential for aerosol dissemination, it is classified as a Tier 1 Select Agent by the U.S. government (CDC). The bacterium predominantly targets host macrophages, where it utilizes specialized mechanisms to escape the phagosome and replicate within the host cytosol while evading the innate immune response (StatPearls). Therapeutic management of tularemia requires antibiotics with effective intracellular penetration, such as aminoglycosides, fluoroquinolones, and tetracyclines, which act by inhibiting bacterial protein synthesis or DNA replication (Frontiers in Microbiology). While natural antibiotic resistance is relatively rare, the pathogen's potential for weaponization makes the development of new vaccines and therapeutic strategies a critical area of biodefense research (PubMed).

Other names

Rabbit fever bacteriumDeer fly fever bacteriumFrancisella tularensis subsp. tularensisFrancisella tularensis subsp. holarctica

Antibiotics targeting this pathogen primarily inhibit bacterial protein synthesis (e.g., aminoglycosides and tetracyclines) or bacterial DNA replication (e.g., fluoroquinolones).