Francisella tularensis
From DrugPedia: A Wikipedia for Drug discovery
Francisella tularensis
It is a pathogenic species of gram-negative bacteria and the causative agent of tularemia or rabbit fever. It is a facultative intracellular bacterium. Due to its ease of spread by aerosol and its high virulence, F. tularensis is classified as a Class A agent by the U.S. government.
| Kingdom | Bacteria |
|---|---|
| Phylum | Proteobacteria |
| Class | Gamma Proteobacteria |
| Order | Thiotrichales |
| Family | Francisellaceae |
| Genus | Francisella |
| Species | F. tularensis |
| Binomial | Francisella tularensis |
Contents |
Surface Characteristics
The O-antigen consisted of the following residues : -2)βD-Quip4NFo(1-->4)α-D-GalpNAcA6NH2(1-->4)α-D-GalpNAcA6NH2(1-->3)βDQuipNAc(1-
Transmission
Infection with F. tularensis can occur via several routes. The most common occurs via skin contact, yielding an ulceroglandular form of the disease. Inhalation of bacteria - particularly biovar tularensis, leads to the potentially lethal pneumonic tularemia. While the pulmonary and ulceroglandular forms of tularemia are more common, other routes of inoculation have been described and include oropharyngeal infection due to consumption of contaminated food and conjunctival infection due to inoculation at the eye.
Pathogenic Activity
F. tularensis is capable of infecting a number of small mammals such as voles, rabbits, and muskrats, as well as humans. Despite this, no case of tularemia has been shown to be initiated by human-to-human transmission. Rather, tularemia is caused by contact with infected animals or vectors such as ticks, mosquitos, and deer flies.
Virulence
The virulence mechanisms for F. tularensis have not been well characterized. Like other intracellular bacteria that break out of phagosomal compartments to replicate in the cytosol, F. tularensis strains produce different hemolytic agents, which may facilitate degradation of the phagosome. A hemolysin activity, named NlyA, with immunological reactivity to Escherichia coli anti-HlyA antibody was identified in biovar novicida. Acid phosphatase AcpA has been found in other bacteria to act as a hemolysin, whereas in Francisella its role as a virulence factor is under vigorous debate.
