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Updated: Aug 9, 2026

In Situ Detection of Bacteria within Paraffin-embedded Tissues Using a Digoxin-labeled DNA Probe Targeting 16S rRNA
Published on: May 21, 2015
Detection of Slackia exigua, Mogibacterium timidum and Eubacterium saphenum from pulpal and periradicular samples
T Hashimura1, M Sato, E Hoshino
1Department of Oral Microbiology, Niigata University School of Dentistry, Japan.
Aim:
The purpose of this study was to detect Slackia exigua from root canal samples using a sensitive PCR amplification method. Mogibacterium timidum and Eubacterium saphenum were also included because of their culture-difficult properties.
Methodology:
The species-specific PCR primers were prepared according to 16S rDNA sequence analysis data, and confirmed to be effective for PCR amplification as species-specific, respectively. A total of 36 clinical samples were obtained during the first visit of root canal treatment.
Results:
The sensitivity of detection was a minimum of 10 organisms for S. exigua and five organisms for M. timidum and E. saphenum, respectively. In seven cases of pulpitis, Sexigua was detected in two cases (29%), and M. timidum in two cases (29%), but E. saphenum was not detected. In 17 cases of root canal treatment, S. exigua was detected in seven cases (41%), M. timidum in 12 cases (71%) and E. saphenum in four cases (24%). In 12 cases of root canal retreatment, S. exigua was detected in three cases (25%), M. timidum in three cases (25%) and E. saphenum in two cases (17%).
Conclusions:
S. exigua, M. timidum and E. saphenum were present in root canal systems, and may be associated with pulpal and periradicular pathosis.

