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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

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

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Author(s):
Pinheiro, Ericka T. [1] ; Candeiro, George T. [1] ; Teixeira, Silvia R. [2] ; Shin, Regina C. [1] ; Prado, Lais C. [1] ; Gavini, Giulio [1] ; Mayen, Marcia P. A. [2]
Total Authors: 7
Affiliation:
[1] Univ Sao Paulo, Sch Dent, Dept Dent, Discipline Endodont, BR-05508000 Sao Paulo, SP - Brazil
[2] Univ Sao Paulo, Inst Biomed Sci, Dept Microbiol, BR-05508000 Sao Paulo, SP - Brazil
Total Affiliations: 2
Document type: Journal article
Source: JOURNAL OF ENDODONTICS; v. 41, n. 9, p. 1441-1444, SEP 2015.
Web of Science Citations: 7
Abstract

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 (Si) 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 165 rRNA sequence. Results: E. faecalis was detected in 77.8% and 72.2% of Si samples using rRNA- and rDNA-based assays, respectively. In contrast, E. faecalis was detected in only 33.3% of 52 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 Si (P < .01) and 52 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 52 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. (AU)