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Updated: Aug 11, 2026

In Situ Detection of Bacteria within Paraffin-embedded Tissues Using a Digoxin-labeled DNA Probe Targeting 16S rRNA
Published on: May 21, 2015
Asaccharolytic anaerobic gram-negative coccobacilli (AAGNC) isolated from infected root canals and periodontal
1Oral Ecology in Health and Infection, Niigata University Graduate School of Medical and Dental Sciences, Japan.
Background/Aims:
Culture-difficult bacteria, including asaccharolytic anaerobic gram-negative coccobacilli (AAGNC), may constitute a predominant group of organisms in oral sites. This study aimed to characterize phylogenetically 10 AAGNC isolated from endodontic lesions and periodontal pockets.
Methods:
16S rDNA sequence and G + C content were determined. Strains sharing more than 98% sequence similarities and similar G + C content were considered the same bacterial species.
Results:
One isolate resembled Dialister pneumosintes (the type species of the genus Dialister) with 35 mol% G + C content and 97% sequence similarity. Of eight isolates having 45-47 mol% G + C content, seven were identified as D. invisus and one resembled Dialister invisus with 97% sequence similarity. However the 16S rDNA sequence similarities with D. pneumosintes were relatively low, indicating the strains may belong to a new genus. The last isolate revealed 35 mol% G + C content, but had higher 16S rDNA sequence similarity with D. invisus than with D. pneumosintes.
Conclusion:
The group of oral AAGNC isolates need to be reclassified.
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