Assessment of intraradicular bacterial composition by terminal restriction fragment length polymorphism analysis.
BACKGROUND
The aim of the study was to assess the bacterial community structures associated with endodontic infections using terminal restriction fragment length polymorphism (T-RFLP), and to investigate the correlation of whole community profiles with the manifestation of particular clinical features.


METHODS
Intraradicular samples were collected from 34 subjects and classified into three study groups based on the observed clinical symptoms: acute (n = 16), sub-acute (n = 8), and asymptomatic (n = 10). Genomic DNA was extracted from each sample, submitted to polymerase chain reaction using a fluorescently labeled 16S ribosomal DNA forward primer, and digested with two tetrameric endonucleases (HhaI and MspI). The terminal restriction fragments (T-RFs) were subsequently discriminated in an automated DNA sequencer, and the results were filtered using a statistics-based criterion.


RESULTS
Totals of 138 (HhaI) and 145 (MspI) unique T-RFs were detected (means 13.1 and 11.9) and there was high inter-subject variability in the bacterial assemblages. Odds-ratio analysis unveiled the existence of higher order groups of positively associated T-RFs, restating the concept that intricate ecological relationships may take place in the root canal space. A significantly greater T-RF prevalence was detected in acute cases, suggesting a straight correlation between species richness and spontaneous pain.


CONCLUSIONS
Overall, no T-RFLP profile representing a specific bacterial consortium could be associated with the manifestation of symptoms of endodontic origin.
Saito
D
D
Department of Oral Diagnosis, Microbiology and Immunology Division, Piracicaba Dental School, State University of Campinas, Piracicaba, São Paulo, Brazil. danielsaito@fop.unicamp.br
Marsh
T L
TL
de Souza Cannavan
F
F
Höfling
J F
JF
Gonçalves
R B
RB
D000190:Actinomyces / Q000145:classification; D000293:Adolescent; D000328:Adult; D001419:Bacteria / Q000145:classification* / Q000235:genetics; D001439:Bacteroides / Q000145:classification; D044884:Campylobacter sputorum / Q000145:classification; D002206:Capnocytophaga / Q000145:classification; D004269:DNA, Bacterial / Q000235:genetics; D003786:Dental Pulp Cavity / Q000382:microbiology*; D003790:Dental Pulp Necrosis / Q000382:microbiology*; D019003:Deoxyribonuclease HpaII; D015252:Deoxyribonucleases, Type II Site-Specific; D005051:Eubacterium / Q000145:classification; D005260:Female; D005417:Flavobacterium / Q000145:classification; D016967:Fusobacterium nucleatum / Q000145:classification; D006801:Humans; D007778:Lactobacillus / Q000145:classification; D008297:Male; D008875:Middle Aged; D010462:Peptostreptococcus / Q000145:classification; D010483:Periapical Diseases / Q000382:microbiology; D012150:Polymorphism, Restriction Fragment Length / Q000235:genetics*; D018720:Prevotella / Q000145:classification; D020357:Selenomonas / Q000145:classification; D017422:Sequence Analysis, DNA; D014678:Veillonella / Q000145:classification; D055815:Young Adult
D004269:DNA, Bacterial; D019003:Deoxyribonuclease HpaII; D015252:Deoxyribonucleases, Type II Site-Specific; C037130:GCGC-specific type II deoxyribonucleases