Prevotella marshii sp. nov. and Prevotella baroniae sp. nov., isolated from the human oral cavity.

Eleven strains of anaerobic Gram-negative bacilli isolated from the human oral cavity were subjected to a comprehensive range of phenotypic and genotypic tests and were found to comprise two homogeneous groups, designated E2 and E4. 16S rRNA gene sequence analysis revealed that members of both groups belonged to the genus Prevotella but were distinct from any species with validly published names. This distinction was confirmed by DNA-DNA hybridization and phenotypic tests. Two novel species are therefore proposed: Prevotella marshii sp. nov. (group E2) and Prevotella baroniae (group E4). Both species are saccharolytic; the end-products of fermentation for P. marshii are acetic, propionic and succinic acids, while P. baroniae produces acetic and succinic acids with minor amounts of isovaleric and isobutyric acids. The G+C content of the DNA of the type strain of Prevotella marshii is 51 mol% and that of Prevotella baroniae is 52 mol%. The type strain for P. marshii is E9.34(T) (=DSM 16973(T)=CCUG 50419(T)) and that for P. baroniae is E9.33(T) (=DSM 16972(T)=CCUG 50418(T)).