Prevotella aurantiaca sp. nov., isolated from the human oral cavity.

Two anaerobic, pigmented, non-spore-forming, Gram-stain-negative, rod-shaped strains isolated from the human oral cavity, OMA31(T) and OMA130, were characterized by determining their phenotypic and biochemical features, cellular fatty acid profiles and phylogenetic positions based on 16S rRNA gene sequence analysis. 16S rRNA gene sequence analysis showed that the new isolates belonged to a single species of the genus Prevotella. The two isolates showed 100 % 16S rRNA gene sequence similarity with each other and were most closely related to Prevotella intermedia ATCC 25611(T) with 96.4 % 16S rRNA gene sequence similarity; the next most closely related strains to the isolates were Prevotella pallens AHN 10371(T) (96.1 %) and Prevotella falsenii JCM 15124(T) (95.3 %). Phenotypic and biochemical characteristics of the isolates were the same as those of P. intermedia JCM 12248(T), P. falsenii JCM 15124(T) and Prevotella nigrescens JCM 12250(T). The isolates could be differentiated from P. pallens JCM 11140( T) by mannose fermentation and alpha-fucosidase activity. Conventional biochemical tests were unable to differentiate the new isolates from P. intermedia, P. falsenii and P. nigrescens. However, hsp60 gene sequence analysis suggested that strain OMA31(T) was not a representative of P. intermedia, P. pallens, P. falsenii or P. nigrescens. Based on these data, a novel species of the genus Prevotella, Prevotella aurantiaca sp. nov., is proposed, with OMA31(T) (=JCM 15754(T)=CCUG 57723(T)) as the type strain.