Francisella tularensis

From Biology-Online Dictionary | Biology-Online Dictionary



A gram-negative non-motile aerobes and non-spore forming bacterium associated in contagious disease tularemia in humans.


Francisella tularensis contains outer membrane peptidoglycan cell wall with pili on the surface with a size at about 0.2 by 0.2 micrometers that can survive in nature up to weeks or more at low temperatures in soil, water and animal carcasses. It has a circular chromosome consisting 52 RNA genes which differentiated into two subspecies known as type A and type B that varies in clinical severity and genomic arrangement. It is covered by capsule-like coat with protrusions on the outer membrane using type 4 pili for pathogenicity to hold on host tissues.

Francisella tularensis has a various route of transmitting infections to humans including ingestion of contaminated food and water, handling of infected animals, inhalation and insects bites. It contains siderophores that grow under limiting iron conditions significant for intracellular replications.

Francisella tularensis is extremely contagious bacterium causing tularemia in human. Its gene mutations interrupt various metabolic and synthetic pathways needed for survival signifying its host dependent for nutrients. In high virulent strains it contains a respiratory burst-inhibiting acid phosphatase an important enzymes to aid the bacterium by avoiding host immune system during infections.

Scientific classification:

Kingdom: Bacteria
Phylum: Proteobacteria
Class: Gammaproteobacteria
Order: Thiotrichales
Family: Francisellaceae
Species: Francisella tularensis 

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