Microbiological evaluation of acute periradicular abscesses by DNA-DNA hybridization / Avaliação microbiológica do acesso periradicular agudo por hibridização DNA-DNA

ABSTRACT

Objective: The purpose of the present investigation was to examine the microbiota of acute periradicular abscesses of endodontic origin by using a molecular genetic method. Study design: Pus was collected by aspiration from 27 cases diagnosed as acute abscesses of endodontic origin, and DNA was extracted to evaluate the occurrence of 49 bacterial species by using whole genomic DNA probes and checkerboard DNA-DNA hybridization. The presence of bacterial DNA in clinical samples was confirmed by polymerase chain reactin with ubiquitous bacterial 16S rRNA gene primers. Results: The results of the checkerboard DNA-DNA hybridization analysis revealed that 37 of the 49 DNA probes tested were reactive wilth one or more samples. The number of bacterial species in the pus samples ranged from 1 to 33 (mean, 5.9). Eighteen of the 27 pus samples were positive for at least one DNA probe. The most prevalent species found were bacteroides forsythus (29.6 percent of the cases); Porphyromonas gingivalis (29.6 percent); Streptococcus constellatus (25.9 percent), Prevotella intermedia (22.2 percent), Prevotella nigrescens (22.2 percent), Fusobacterium periodonticum (18.5 percent), Fusobacterium nucleatum subspecies nucleatum (18.5 percent), and Eikenella corrodens (18.5 percent). Conclusions: The microbiologic data of the present investigation indicated that molecular genetic methods could provide additional knowledge regarding the microbiota of acute periradicular abscesses by detecting bacterial species that are difficult-or even impossible-to grow