CHARACTERIZATION OF PREVOTELLA-INTERMEDIA AND PREVOTELLA-NIGRESCENS BY ENZYME-PRODUCTION, RESTRICTION-ENDONUCLEASE AND RIBOSOMAL-RNA GENE RESTRICTION ANALYSES

Restriction endonuclease analysis, rRNA gene restriction analysis (rib otyping), multilocus enzyme electrophoresis and lipase production were investigated for their potential to differentiate isolates belonging to the closely-related species Prevotella intermedia and Prevotella ni grescens. Of 122 strains identified originally as P. intermedia, 52 we re assigned to P. intermedia and 68 to P. nigrescens using multilocus enzyme electrophoresis. All 39 P. intermedia and 52 out of 53 P. nigre scens tested produced lipase. Restriction endonuclease analysis identi fied clonal variants, but did not facilitate the differentiation of st rains into species. Taq I ribotyping of 99 strains revealed that all P . intermedia demonstrated a species-specific fragment of 0.40 kbp, whi ch was always associated with a second fragment of 0.57 kbp, and all P . nigrescens tested shared a species-specific fragment of 2.21 kbp. Tw o strains atypical by multilocus enzyme electrophoresis had none of th e above species-specific fragments. Thus, lipase production and restri ction endonuclease analysis did not distinguish between P. intermedia and P. nigrescens, but Taq I ribotyping did and also allowed the chara cterization of individual strains.