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

Autor(es)

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]

Afiliação do(s) autor(es)

^[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

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF ENDODONTICS; v. 41, n. 9, p. 1441-1444, SEP 2015.
• Citações Web of Science: 7

Resumo

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)

• Processo FAPESP: 09/52661-5 - Estudo de Enterococcus faecalis em infecções endodônticas: prevalência, quantificação, viabilidade, fatores de virulência e diversidade genética
• Beneficiário: Ericka Tavares Pinheiro
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores