Comparison of the Bacterial Composition and Structure in Symptomatic and Asymptomatic Endodontic Infections Associated with Root-Filled Teeth Using Pyrosequencing

<div><p>Residual microorganisms and/or re-infections are a major cause for root canal therapy failure. Understanding of the bacterial content could improve treatment protocols. Fifty samples from 25 symptomatic and 25 asymptomatic previously root-filled teeth were collected from Sudanese patients with periradicular lesions. Amplified 16S rRNA gene (V1-V2) variable regions were subjected to pyrosequencing (FLX 454) to determine the bacterial profile. Obtained quality-controlled sequences from forty samples were classified into 741 operational taxonomic units (OTUs) at 3% dissimilarity, 525 at 5% dissimilarity and 297 at 10% dissimilarity, approximately corresponding to species-, genus- and class levels. The most abundant phyla were: <i>Firmicutes</i> (29.9%), <i>Proteobacteria</i> (26.1%), <i>Actinobacteria</i> (22.72%), <i>Bacteroidetes</i> (13.31%) and <i>Fusobacteria</i> (4.55%). Symptomatic patients had more <i>Firmicutes</i> and <i>Fusobacteria</i> than asymptomatic patients, while asymptomatic patients showed more <i>Proteobacteria and Actinobacteria</i>. Interaction of disease status and age was observed by two-way ANOSIM. Canonical correspondence analysis for age, tooth restoration and disease status showed a correlation of disease status with the composition and prevalence of different members of the microbial community. The pyrosequencing analysis revealed a distinctly higher diversity of the microbiota compared to earlier reports. The comparison of symptomatic and asymptomatic patients showed a clear association of the composition of the bacterial community with the presence and absence of symptoms in conjunction with the patients’ age.</p> </div

Depicts the mean percentage abundance of the top ten bacterial taxa contributing to more than 52.6% dissimilarity among the two types of samples (symptomatic = black, asymptomatic = grey) from previously root-filled teeth as identified by Bray-Curtis model of SIMPER analysis.

<p>Depicts the mean percentage abundance of the top ten bacterial taxa contributing to more than 52.6% dissimilarity among the two types of samples (symptomatic = black, asymptomatic = grey) from previously root-filled teeth as identified by Bray-Curtis model of SIMPER analysis.</p

Abundance of the different bacterial phyla detected in clinical samples of root-canal treated teeth.

<p>Abundance of the different bacterial phyla detected in clinical samples of root-canal treated teeth.</p

SIMPER Analysis (Bray-Curtis model): Mean percentage abundance (square root transformed) values of species-level OTUs (A; 3% dissimilarity) and genus-level OTUs (B; 5% dissimilarity) contributing to differences in symptomatic versus asymptomatic cases of secondary and persistent root canal infections.

<p>SIMPER Analysis (Bray-Curtis model): Mean percentage abundance (square root transformed) values of species-level OTUs (A; 3% dissimilarity) and genus-level OTUs (B; 5% dissimilarity) contributing to differences in symptomatic versus asymptomatic cases of secondary and persistent root canal infections.</p

Summarizes the distribution of the top 25 most abundant genera in symptomatic (red) and asymptomatic cases (blue) with their relative abundance data (depicted as bars) and prevalence values (given as numbers next to bars).

<p>Summarizes the distribution of the top 25 most abundant genera in symptomatic (red) and asymptomatic cases (blue) with their relative abundance data (depicted as bars) and prevalence values (given as numbers next to bars).</p

Global economic burden of unmet surgical need for appendicitis

Background There is a substantial gap in provision of adequate surgical care in many low- and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US $92 492 million using approach 1 and$73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was $95 004 million using approach 1 and$75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially

Global economic burden of unmet surgical need for appendicitis

Background There is a substantial gap in provision of adequate surgical care in many low- and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US $92 492 million using approach 1 and$73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was $95 004 million using approach 1 and$75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially