Microbial transformation from normal oral microbiota to acute endodontic infections

Abstract

Background: Endodontic infections are a leading cause of oro-facial pain and tooth loss in western countries, and may lead to severe life-threatening infections. These infections are polymicrobial with high bacterial diversity. Understanding the spatial transition of microbiota from normal oral cavities through the infected root canal to the acute periapical abscess can improve our knowledge of the pathogenesis of endodontic infections and lead to more effective treatment. We obtained samples from the oral cavity, infected root canal and periapical abscess of 8 patients (5 with localized and 3 with systemic infections). Microbial populations in these samples were analyzed using next-generation sequencing of 16S rRNA amplicons. Bioinformatics tools and statistical tests with rigorous criteria were used to elucidate the spatial transition of the microbiota from normal to diseased sites.

Microbiology and Treatment of Acute Apical Abscesses

“…The overall diversity of abscesses as revealed by pyrosequencing was much higher than previously reported. Most of these findings were confirmed by another study using pyrosequencing, which revealed representatives of 11 phyla and Fusobacterium as the most abundant genus (92).…”

“…Abscesses are polymicrobial infections for which culture studies have reported a mean number of species ranging from 2 to 8.5 per pus specimen (41-43, 45, 46, 48, 49, 96, 97, 182), while molecular studies have revealed a mean of 12 to 18 species/phylotypes per case (83,95). Findings from pyrosequencing studies suggest that these numbers can be much higher (91,92). What has become evident from most studies comparing acute apical abscesses and asymptomatic endodontic infections is that there are different dominant species in the communities, and the former are usually characterized by a significantly higher species richness than that of the latter (83,91,95,159).…”

“…The fourth generation of studies involved closed-ended molecular analyses with PCR and DNA hybridization assays (e.g., reversecapture checkerboard) in large-scale clinical studies to investigate the prevalence and association of cultivable and as-yet-uncultivated bacteria with abscesses (88)(89)(90). A fifth generation has been possibly heralded by the use of pyrosequencing technology for a deep-coverage open-ended analysis of abscess samples (91,92) (see below).…”

“…Even so, studies have reported some discrepancies between bacterial community profiles for matched samples taken from the root canal and abscess aspirates (92,161). The differences observed suggest that some selection of species occurs as the infection advances from the canal to the periradicular tissues.…”

The Lung Microbiome in Moderate and Severe Chronic Obstructive Pulmonary Disease

“…Coribacteriales, a member of the gram-positive phylum Actinobacteria, were increased in the COPD and LLQ analyses. This increase was extended down to the genus level: Atopobium, a vaginal commensal and member of the oral flora [21] and Cryptobacterium, a cause of dental abscess [22]. Two orders in the grampositive phylum Firmicutes were differentially abundant.…”