Isolation and identification of Prevotella tannerae from endodontic infections.

Black-pigmented bacteria are often isolated from endodontic infections. Five strains of black-pigmented bacteria isolated from endodontic infections could not be identified in our laboratory. The purpose of this study was to sequence the 16S rRNA gene of the five unknown isolates and identify the organisms. The 16S rRNA genes from the unknown organisms were cloned, sequenced, and determined to be Prevotella tannerae. In addition, samples from endodontic infections were surveyed for the presence of the organism. When 118 samples from endodontic infections were examined using polymerase chain reaction with specific primers for P. tannerae, 60% of the samples were positive for the presence of the organism. This suggests that P. tannerae is commonly present in endodontic infections and could be a potential pathogen.