Corynebacterium confusum sp. nov., isolated from human clinical specimens.

Three strains of a previously unknown coryneform bacterium were isolated from two patients with foot infections and from a blood culture of a third patient. The three non-lipophilic strains exhibited very slow fermentative acid production from glucose but not from maltose or sucrose, nitrate reductase activity, no tyrosinase activity and the presence of small amounts of tuberculostearic acid as the most significant phenotypic features. Differentiation of these strains from all other presently defined coryneform bacteria was readily achieved. Chemotaxonomic investigations revealed that the three strains unambiguously belonged to the genus Corynebacterium. Comparative 16S rRNA gene sequence analysis demonstrated that the isolates were almost identical and represented a new subline within the genus Corynebacterium, for which the designation Corynebacterium confusum sp. nov. is proposed. The type strain of Corynebacterium confusum is CCUG 38267T.