Species-directed 16S rRNA gene nested PCR detection of Olsenella species in association with endodontic diseases

To investigate the occurrence of Olsenella uli and Olsenella profusa in samples taken from infections of endodontic origin using a devised 16S RNA gene-based nested PCR protocol.DNA extracted from clinical samples was initially amplified using universal 16S rRNA gene primers followed by a second round of amplification using the first PCR products to detect a specific fragment of either O. uli or O. profusa 16S rRNA gene. Olsenella uli was detected in 27% of samples from teeth with asymptomatic periradicular lesions and in 20% of pus samples taken from symptomatic (abscess) lesions. Olsenella profusa was detected in 7% of asymptomatic teeth and in 13% of symptomatic teeth. A new Olsenella phylotype was also detected.Olsenella species can take part in the microbiota associated with infections of the root canal of human teeth and a role in the pathogenesis of periradicular diseases is suspected.The present study demonstrates that molecular genetic methods keep expanding the list of candidate endodontic pathogens to include Olsenella species.