Arcicella rosea sp. nov., isolated from tap water.

Strain TW5(T), a motile, Gram-negative bacterium that produced pale-pink colonies, was isolated from tap water on R2A agar at 20 degrees C. 16S rRNA gene sequence studies showed that the strain clustered with Arcicella aquatica (99.0 % sequence similarity to the type strain). The main polyamine present was spermidine, the quinone system comprised menaquinone MK-7 and the polar lipid profile consisted of a mixture of aminophospholipids, aminolipids, glycolipids and uncharacterized polar lipids. The fatty acid profile was slightly different from that reported for A. aquatica. The results of DNA-DNA hybridizations and physiological and biochemical tests clearly allowed both genotypic and phenotypic differentiation of the isolate from A. aquatica. On the basis of these results, it is proposed that the strain should be classified within a novel species of the genus Arcicella. The name proposed for this taxon is Arcicella rosea sp. nov.; the type strain is TW5(T) (=CCUG 55942(T) =CCM 7523(T)).