The family francisellaceae

Duncan J. Colquhoun, Pär Larsson, Samuel Duodu, Mats Forsman

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review

11 Citations (Scopus)

Abstract

The family Francisellaceae Sjöstedt (The proteobacteria, part B. Bergey's Manual of Systematic Bacteriology. Springer-Verlag, New York, 2005, pp. 200-210), most closely related to Caedibacter taeniospiralis and Fangia hongkongensis, within the Gammaproteobacteria, comprises the single type genus Francisella Olsufjev (J Hyg Epidemiol Microbiol Immunol, 14:67-74, 1970). The genus consists of small (0.7-1.7 μm), nonmotile, Gram-negative (staining faintly), aerobic coccobacilli, which may or may not require additional cysteine (or cystine) for culture, weakly catalase positive, and most (but not all) produce H2S when cultured in cysteine-containing media. Members of the Francisella grow with entire, slightly convex pale white or gray, semitranslucent, mucoid colonies. Incubation time and temperature is dependent on species and strain, but they are relatively slowly growing. Many are capable of facultative intracellular growth. The Francisella have a trans-global distribution, although most isolates have been recovered in the Northern Hemisphere. The type species is F. tularensis, which is further divided into four subspecies, i.e., tularensis, holarctica, mediasiatica, and novicida. Subspecies tularensis and holarctica commonly called biotypes A and B, respectively, can in turn be further divided into several subpopulations based on genetic analysis. F. tularensis causes the disease tularemia in mammalian species and represents a potential category A bioterror weapon. Several members of the genus, e.g., F. noatunensis (subspecies noatunensis and orientalis) and F. halioticida, are highly virulent pathogens of fish and molluscs. These species can be readily distinguished from the remainder of the genus by their lower optimal and cardinal growth temperatures. Despite the relatively small number of described species, an increasing body of evidence exists for the existence of a large and diverse environmental population of as-yet undescribed Francisella species.

Original languageEnglish
Title of host publicationThe Prokaryotes
Subtitle of host publicationGammaproteobacteria
PublisherSpringer-Verlag Berlin Heidelberg
Pages287-314
Number of pages28
ISBN (Electronic)9783642389221
ISBN (Print)364238921X, 9783642389214
DOIs
Publication statusPublished - 1 Jul 2013
Externally publishedYes

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