The Genera Bergeyella and Weeksella
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The Genera Bergeyella and Weeksella CELIA J. HUGO, BRITA BRUUN AND PIET J. JOOSTE
Introduction Bergeyella and Weeksella have a history of being a separate group of organisms in the flavobacteria-grouping. They were originally treated as one genus (Weeksella) with two species, namely, W. virosa (Holmes et al., 1986a) and W. zoohelcum (Holmes et al., 1986b). Since 1994, however, they were separated into two genera in the Flavobacteriaceae family (Vandamme et al., 1994) as discussed in the introductory chapter about this family (see the chapter An Introduction to the Family Flavobacteriaceae in this Volume). Strains of both of these genera, especially Bergeyella with its frequent association with animal bite wounds, are found in clinical specimens. The aim of this chapter is to provide more detail on the taxonomy, phylogeny, habitat, isolation and preservation, identification, pathogenicity and applications of these two genera.
Taxonomy and Phylogeny Formerly known as Centers for Disease Control (CDC) groups IIf (Weeksella) and IIj (Bergeyella), these two genera were originally isolated and grouped by the late Elizabeth O. King and her successors (Tatum et al., 1974). These organisms have also been referred to as Flavobacterium Group 3 (Pickett and Manclark, 1970a), Group 1 (Olsen and Ravn, 1971) and “Flavobacterium genitale” (Price and Pickett, 1981). After Holmes and Owen (1979) emended the description of Flavobacterium, they found Groups IIf and IIj conformed to the emended description and later concluded that they probably should be placed in a separate genus (1981). Dees et al. (1981) were of the opinion that Group IIj and Group IIf (1986) should be accommodated in Flavobacterium on the basis of cellular fatty acid composition. Other authors, however, regarded Group IIj as intermediate in terms of its characteristics between the genera Brucella and Moraxella (Owen and Snell, 1973; Saphir and Carter, 1976; Bailie et al., 1978).
In 1981, Holmes and Owen allocated the flavobacteria into four groups (the recent correct names of the organisms are given in square brackets): Group A (F. balustinum [Chryseobacterium balustinum; Vandamme et al., 1994], F. breve [Empedobacter brevis; Vandamme et al., 1994], F. indoltheticum [Chryseobacterium indoltheticum; Vandamme et al., 1994], F. meningosepticum [Chryseobacterium meningosepticum; Vandamme et al., 1994], and remaining CDC Group IIb strains), Group B (F. odoratum [Myroides odoratus; Vancanneyt et al., 1996]), Group C (CDC Group IIk, type 2 and “Group IIk, type 3” [Sphingobacterium species; Yabuuchi et al., 1983; Takeuchi and Yokota, 1992]), and Group D (CDC Groups IIf and IIj). The organisms in Group D were then frequently referred to as Flavobacterium-like. In 1986, Holmes et al. proposed the names “Weeksella virosa” (1986a) for strains belonging to CDC Group IIf and “Weeksella zoohelcum” (1986b) for strains belonging to CDC Group IIj, respectively. They also included these two species in the family Cytophagaceae,
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