Francisella

A genus of nonmotile, nonsporeforming, aerobic bacteria that contain small, Gram-negative cocci and rods. Capsules are rarely produced and the cells may show bipolar staining. These organisms are highly pleomorphic; they do not grow on plain agar or in liquid media without special enrichment; they are pathogenic and cause tularemia in humans. The type species is F. tularensis.

- F. tularensis a bacterial species that causes tularemia in humans, transmitted from wild animals by bloodsucking insects or by contact with infected animals such as ticks; main sources of infection are rabbits and ticks; it can penetrate unbroken skin to cause infection, and if inhaled can cause a rapidly fatal pneumonia; type species of the genus F.. SYN: Pasteurella tularensis.

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Fran·ci·sel·la (fran-sĭ-selґə) [E. Francis] a genus of gram-negative bacteria of the familyFrancisellaceae, consisting of small, pleomorphic, rod-shaped or coccoid cells. Organisms are aerobic and nonmotile, do not produce endospores, and are pathogenic in various animals, particularly lagomorphs. The type species is F. tularenґsis.