Francisella species

Background

Microbiology

• A genus of Gram-negative coccobacilli
• Includes a number of important species
  • Human pathogens
    • Francisella tularensis
    • Francisella philomiragia
    • Francisella hispaniensis
  • Fish pathogens
    • Francisella noatunensis subsp. orientalis
    • Francisella halioticida
  • Environmental species
    • Francisella guangzhouensis
  • Tick endosymbiont
    • Francisella persica (previously Wolbachia persica)
    • Dermacentor andersoni symbiont
    • Symbiont B of the soft tick Ornithodoros moubata

Identification

Test	F. tularensis			F. philomiragia	F. hispaniensis
	tularensis	holarctica	novicida
Cysteine growth requirement	+	+	–	–	–
Growth in broth with 6% NaCl	–	–	+/–	+	NA
Motility	–	–	–	–	NA
Oxidase	–	–	–	+	+
Nitrate reduction	–	–	–	–	NA
Acid from glucose	+/–	+/–	+/–	+/–	+
Acid from glycerol	+	–	+	+	+
Gelatin hydrolysis	–	–	–	+/–	NA
Virulence in humans	high	intermediate	low	low	low
Virulence in rabbits	high	low	low	NA	NA