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NC Department of Health and Human Services
State Laboratory of Public Health
N.C. Public Health Home

Bioterrorism - Agents of Concern

Francisella tularensis

Francisella tularensis on CHAB
F. tularensis on CHAB @ 48hrs (PHIL)

Colony Characteristics

  • Poor growth on sheep blood agar.
  • Growth on chocolate, Thayer-Martin, and horse blood agar: 1-3 mm, gray-white to bluish-gray with a smooth flat surface at 48-72 hrs.
  • Ability to grow on sheep blood agar diminishes after sub-culturing.
  • Does not grow on MacConkey or EMB agar.

Francisella tularensis 48 hours Horse Blood
F. tularensis on Horse Blood Agar @48 hrs (NCSLPH)
Francisella tularensis on CHAB
F. tularensis on Sheep Blood Agar @48 hrs (NCSLPH)


Francisella microscopic

  • Faintly staining, very tiny Gram-negative coccobacillus, most appear as single cells.
  • Cells appear smaller than those of Brucella spp.

Oxidase Negative
Urease Negative

Any sample that cannot be ruled out by these methods should be forwarded to the NCSLPH.

SLPH Bioterrorism Information