Real-time polymerase chain reaction quantification of Porphyromonas gingivalis and Tannerella forsythia in primary endodontic infections.
BACKGROUND
Porphyromonas gingivalis and Tannerella forsythia are anaerobic bacteria commonly involved in root canal infections. Although previous investigations have assessed these species by strictly qualitative approaches, accurate determination of their cell levels by a sensitive quantitative technique may contribute with additional information regarding relevance in pain of endodontic origin.


METHODS
The root canal levels of P. gingivalis, T. forsythia, and total bacteria were investigated by a quantitative polymerase chain reaction (PCR) assay based on unique copy molecular markers. A total of 32 symptomatic (n = 14) and asymptomatic (n = 18) cases of endodontic infections were analyzed. Root canal samples were collected; genomic DNA was extracted and submitted to SYBR Green I real-time PCR targeting the rgpB (P. gingivalis), bspA (T. forsythia), and rpoB (total bacteria) single copy genes.


RESULTS
Overall, P. gingivalis, T. forsythia, and the coexistence of both species were encountered in 28%, 66%, and 22% of the subjects, respectively. P. gingivalis and T. forsythia levels ranged from 5.65 x 10(-6) to 1.20 x 10(-2) and from 5.76 x 10(-6) to 1.35 x 10(-1). T. forsythia was highly prevalent and numerous in the study groups, whereas P. gingivalis was moderately frequent and less abundant, displaying 19-fold lower average levels than the former.


CONCLUSIONS
The endodontic levels of P. gingivalis and T. forsythia, individually or in conjunction, did not display significant associations with the manifestation of pain of endodontic origin.
Department of Oral Diagnosis, Microbiology and Immunology Division, Piracicaba Dental School, State University of Campinas, São Paulo, Brazil.
Daniel
D
Saito
Luiz Lehmann
LL
Coutinho
Cristiane Pereira
CP
Borges Saito
Siu Mui
SM
Tsai
José Francisco
JF
Höfling
Reginaldo Bruno
RB
Gonçalves
D018829:Adhesins, Bacterial / Q000032:analysis; D000293:Adolescent; D000328:Adult; D000942:Antigens, Bacterial / Q000032:analysis; D001426:Bacterial Proteins / Q000032:analysis; D016866:Bacteroidaceae Infections / Q000382:microbiology*; D001439:Bacteroides / Q000302:isolation & purification*; D001442:Bacteroides Infections / Q000382:microbiology*; D015169:Colony Count, Microbial; D003546:Cysteine Endopeptidases / Q000032:analysis; D004269:DNA, Bacterial / Q000032:analysis; D003786:Dental Pulp Cavity / Q000382:microbiology*; D003790:Dental Pulp Necrosis / Q000382:microbiology*; D005260:Female; D000080867:Gingipain Cysteine Endopeptidases; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods*; D016966:Porphyromonas gingivalis / Q000302:isolation & purification*; D055815:Young Adult
D018829:Adhesins, Bacterial; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C116104:BspA protein, Bacteroides; D004269:DNA, Bacterial; D000080867:Gingipain Cysteine Endopeptidases; D003546:Cysteine Endopeptidases