RNA-based Assay Demonstrated Enterococcus faecalis Metabolic Activity after Chemomechanical Procedures.

Autor:	Pinheiro ET; Discipline of Endodontics, Department of Dentistry, School of Dentistry, University of São Paulo, São Paulo, Brazil. Electronic address: erickapinheiro@usp.com., Candeiro GT; Discipline of Endodontics, Department of Dentistry, School of Dentistry, University of São Paulo, São Paulo, Brazil., Teixeira SR; Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil., Shin RC; Discipline of Endodontics, Department of Dentistry, School of Dentistry, University of São Paulo, São Paulo, Brazil., Prado LC; Discipline of Endodontics, Department of Dentistry, School of Dentistry, University of São Paulo, São Paulo, Brazil., Gavini G; Discipline of Endodontics, Department of Dentistry, School of Dentistry, University of São Paulo, São Paulo, Brazil., Mayer MP; Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
Jazyk:	angličtina
Zdroj:	Journal of endodontics [J Endod] 2015 Sep; Vol. 41 (9), pp. 1441-4. Date of Electronic Publication: 2015 Jun 10.
DOI:	10.1016/j.joen.2015.04.020
Abstrakt:	Introduction: Because ribosomal RNA (rRNA) indicates metabolic cell activity, this study aimed to evaluate the sensitivity of rRNA-based quantitative polymerase chain reaction (RT-qPCR) for the identification of active Enterococcus faecalis in root canals samples compared with a method based on ribosomal DNA (rDNA) (rRNA genes). Methods: Samples were taken from 18 teeth with persistent/secondary intraradicular infection before (S1) and after (S2) chemomechanical preparation. RNA and DNA were extracted, and complementary DNA was synthesized from RNA using RT-PCR. Complementary DNA and genomic DNA were subjected to quantitative polymerase chain reaction with primers complementary for E. faecalis 16S rRNA sequence. Results: E. faecalis was detected in 77.8% and 72.2% of S1 samples using rRNA- and rDNA-based assays, respectively. In contrast, E. faecalis was detected in only 33.3% of S2 samples using rDNA as the template compared with 61.1% using the rRNA-based method. The median concentration of rRNA copies of E. faecalis was significantly higher than rDNA copies, indicating a higher sensitivity for the method targeting rRNA in both S1 (P < .01) and S2 samples (P < .05). After chemomechanical preparation, the number of rRNA and rDNA copies was significantly reduced (P < .05). The high ratio of rRNA to rDNA copies in S2 samples suggested that active E. faecalis persisted in root canals after chemomechanical preparation. Conclusions: The RT-qPCR assay provides a sensitive method for the identification of active E. faecalis from endodontic samples. Furthermore, the rRNA-based assay indicated that E. faecalis viable cells persisted in treated root canals, suggesting that it may be a useful tool for monitoring microbial load during endodontic treatment. (Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)
Databáze:	MEDLINE
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