The goals of this study were to better understand the ecology of oral subgingival communities in health and periodontitis and elucidate the relationship between inflammation and the subgingival microbiome. Accordingly, we used 454-pyrosequencing of 16S rRNA gene libraries and quantitative PCR to characterize the subgingival microbiome of 22 subjects with chronic periodontitis. Each subject was sampled at two sites with similar periodontal destruction but differing in the presence of bleeding, a clinical indicator of increased inflammation. Communities in periodontitis were also compared with those from 10 healthy individuals. In periodontitis, presence of bleeding was not associated with different α-diversity or with a distinct microbiome, however, bleeding sites showed higher total bacterial load. In contrast, communities in health and periodontitis largely differed, with higher diversity and biomass in periodontitis. Shifts in community structure from health to periodontitis resembled ecological succession, with emergence of newly dominant taxa in periodontitis without replacement of primary health-associated species. That is, periodontitis communities had higher proportions of Spirochetes, Synergistetes, Firmicutes and Chloroflexi, among other taxa, while the proportions of Actinobacteria, particularly Actinomyces, were higher in health. Total Actinomyces load, however, remained constant from health to periodontitis. Moreover, an association existed between biomass and community structure in periodontitis, with the proportion of specific taxa correlating with bacterial load. Our study provides a global-scale framework for the ecological events in subgingival communities that underline the development of periodontitis. The association, in periodontitis, between inflammation, community biomass and community structure and their role in disease progression warrant further investigation.

/pdf/the-subgingival-microbiome-in-health-and-periodontitis-and-2opy2xn5y3.pdf

The subgingival microbiome in health and periodontitis and its relationship with community biomass and inflammation

Rationale: Results from 16S rDNA-encoding gene sequence–based, culture-independent techniques have led to conflicting conclusions about the composition of the lower respiratory tract microbiome. Objectives: To compare the microbiome of the upper and lower respiratory tract in healthy HIV-uninfected nonsmokers and smokers in a multicenter cohort. Methods: Participants were nonsmokers and smokers without significantcomorbidities.Oralwashesandbronchoscopicalveolarlavages were collected in a standardized manner. Sequence analysis of bacterial 16S rRNA-encoding genes was performed, and the neutral modelincommunityecologywasusedtoidentifybacteriathatwere the most plausible members of a lung microbiome. Measurements and Main Results: Sixty-four participants were enrolled. Mostbacteriaidentifiedinthelungwerealsointhemouth,butspecific bacteria such as Enterobacteriaceae, Haemophilus, Methylobacterium, and Ralstonia species were disproportionally represented in the lungs compared with values predicted by the neutral model. Tropheryma was

https://www.atsjournals.org/doi/pdf/10.1164/rccm.201210-1913OC

Comparison of the Respiratory Microbiome in Healthy Nonsmokers and Smokers

Cigarette smokers have an increased risk of infectious diseases involving the respiratory tract. Some effects of smoking on specific respiratory tract bacteria have been described, but the consequences for global airway microbial community composition have not been determined. Here, we used culture-independent high-density sequencing to analyze the microbiota from the right and left nasopharynx and oropharynx of 29 smoking and 33 nonsmoking healthy asymptomatic adults to assess microbial composition and effects of cigarette smoking. Bacterial communities were profiled using 454 pyrosequencing of 16S sequence tags (803,391 total reads), aligned to 16S rRNA databases, and communities compared using the UniFrac distance metric. A Random Forest machine-learning algorithm was used to predict smoking status and identify taxa that best distinguished between smokers and nonsmokers. Community composition was primarily determined by airway site, with individuals exhibiting minimal side-of-body or temporal variation. Within airway habitats, microbiota from smokers were significantly more diverse than nonsmokers and clustered separately. The distributions of several genera were systematically altered by smoking in both the oro- and nasopharynx, and there was an enrichment of anaerobic lineages associated with periodontal disease in the oropharynx. These results indicate that distinct regions of the human upper respiratory tract contain characteristic microbial communities that exhibit disordered patterns in cigarette smokers, both in individual components and global structure, which may contribute to the prevalence of respiratory tract complications in this population.

http://www.bushmanlab.org/assets/pdf/publications/21188149.pdf

Disordered microbial communities in the upper respiratory tract of cigarette smokers.

Aim
Although it is established that peri-implantitis is a bacterially induced disease, little is known about the bacterial profile of peri-implant communities in health and disease. The purpose of the present investigation was to examine the microbial signatures of the peri-implant microbiome in health and disease.

/pdf/pyrosequencing-reveals-unique-microbial-signatures-snqhtjomhd.pdf

Pyrosequencing reveals unique microbial signatures associated with healthy and failing dental implants.

Objectives. This paper aims to review the evidence on the potential roles of modifiable and nonmodifiable risk factors associated with periodontal disease. Data. Original articles that reported on the risk factors for periodontal disease were included. Sources. MEDLINE (1980 to Jan 2014), PubMed (using medical subject headings), and Google Scholar were searched using the following terms in different combinations: “periodontal disease,” “periodontitis,” “risk factors,” and “causal.” This was supplemented by hand-searching in peer-reviewed journals and cross-referenced with the articles accessed. Conclusions. It is important to understand the etiological factors and the pathogenesis of periodontal disease to recognize and appreciate the associated risk factors. As periodontal disease is multifactorial, effective disease management requires a clear understanding of all the associated risk factors.

/pdf/risk-factors-of-periodontal-disease-review-of-the-literature-197l632ylb.pdf

Risk Factors of Periodontal Disease: Review of the Literature

The subgingival microbiome is largely uncultivated, and therefore, cultivation-based and targeted molecular approaches have limited value in examining the effect of smoking on this community. We tested the hypothesis that the subgingival biofilm is compositionally different in current and never-smokers by using an open-ended molecular approach for bacterial identification. Subgingival plaque from deep sites of current and never-smokers matched for disease was analyzed by 16S sequencing. Smokers demonstrated greater abundance of Parvimonas, Fusobacterium, Campylobacter, Bacteroides, and Treponema and lower levels of Veillonella, Neisseria, and Streptococcus. Several uncultivated Peptostreptococci, Parvimonas micra, Campylobacter gracilis, Treponema socranskii, Dialister pneumosintes, and Tannerella forsythia were elevated in this group, while Veillonella sp. oral clone B2, Neisseria sp. oral clone 2.24, Streptococcus sanguinis, and Capnocytophaga sp. clone AH015 were at lower levels. The microbial profile of smoking-associated periodontitis is distinct from that of non-smokers, with significant differences in the prevalence and abundance of disease-associated and health-compatible organisms.

/pdf/subgingival-microbial-profiles-of-smokers-with-periodontitis-3begnfmv3l.pdf

A.Y. Shchipkova

Papers

Subgingival Microbial Profiles of Smokers with Periodontitis