The Family Dermatophilaceae
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The Family Dermatophilaceae ERKO STACKEBRANDT
The family Dermatophilaceae embraces two genera, Dermatophilus and Kineosphaera. Dermatophilus congolensis was first described by Van Saceghem (1915) as the causative organism of a disease he named successively as “dermatite granuleuse,” “dermatose contagieuse ou impetigo contagieux,” and “dermatose dite contagieuse des bovides, impetigo tropical des bovides.” This acute, subacute or chronic exudative and proliferative skin disease is prevalent in the humid tropics and subtropics and affects more than thirty animal species and man (Zaria, 1993; Table 1), but animals are also affected in countries of the Northern hemisphere. The disease (also referred to as streptotrichosis, pitted keratolysis, strawberry foot rot, lumpy wool, rain scald or dermatophilosis, depending on the host infected and clinical signs) is economically important, occurring in domestic cattle in tropical regions, sheep in high-rainfall areas, and also wild species (see Zaria [1993] for references). Recently, the genus Kineosphaera has been included in the family (Liu et al., 2002). Kineosphaera limosa, not reported to be pathogenic, has been isolated from a sequential batch reactor running under alternating anaerobic and aerobic conditions to study biological phosphate removal.
Phylogeny Austwick (1958) described the family Dermatophilaceae to include the two actinomycete genera Dermatophilus and Geodermatophilus. The classification of these two genera in a family was based on a single but very unique morphological feature, i.e., division in both transverse and longitudinal planes, which leads to the formation of packets or clusters of cuboid cells or cocci. Considering growth characteristics and developmental stages (Luedemann, 1968), as well as chemical properties (Lechevalier and Lechevalier, 1981; Stackebrandt, 1983), the two previously described species D. congolensis and G. obscurus differ significantly from each other. It was therefore not surprising that these species
are located at different positions in the dendrogram derived from 16S rRNA cataloguing data. While G. obscurus, together with Frankia, Modestobacter (Mevs et al., 2000) and Blastococcus species (Ahrens and Moll, 1970; Urzi et al., 2003), constitutes an individual subline of descent (Stackebrandt et al., 1983; Hahn et al., 1989), D. congolensis was found to group by itself within a phylogenetically tight but phenotypic ally broad cluster, which harbors arthrobacteria, micrococci, cellulomonads and relatives, microbacteria, brevibacteria and others. Consequently, the family Dermatophilaceae was redefined (Stackebrandt and Schumann, 2002) to contain Dermatophilus as the only genus, embracing two species, D. congolens (Van Saceghem, 1915) and D. chelonae (Masters et al., 1995). The type strain of D. congolensis has been deposited as ATCC 14637T = DSM 44180T = JCM 8106T = NCTC 13039T = NRRL B-2350T. The type strain W16T of D. chelonae is available as ATCC 51576T = CIP 104541T = DSM 4417
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