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

Aims: 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. Methods and Results: 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. Conclusions: 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. Significance and Impact of the Study: The present study demonstrates that molecular genetic methods keep expanding the list of candidate endodontic pathogens to include Olsenella species.