Diabetes and respiratory system including tuberculosis - challenges

Exploring the accuracy of third-generation Nanopore Sequencing technology for detecting mycobacterium tuberculosis in patients with diabetes mellitus

OBJECTIVE

To explore the diagnostic value of third-generation nanopore sequencing technology in patients with diabetes mellitus suspected of pulmonary tuberculosis.

METHODS

Samples, including sputum and bronchoalveolar lavage fluid(BALF), were collected from patients with diabetes mellitus suspected of pulmonary tuberculosis who were admitted from October 2021 to August 2023. Nanopore sequencing, acid-fast bacilli (AFB) smear, mycobacterial solid culture, Xpert MTB/RIF, and DNA detection were performed, and their diagnostic efficacy was compared.

RESULTS

Third-generation nanopore sequencing technology exhibited high accuracy in diagnosing pulmonary tuberculosis in patients with diabetes mellitus. Compared to traditional methods, nanopore sequencing showed significantly improved sensitivity (76.80 %), negative predictive value (30.40 %), coincidence (77.92 %), and diagnostic accuracy (AUC = 0.822). Combined detection with Xpert achieved the highest diagnostic performance, with increased sensitivity (81.20 %), positive predictive value (98.20 %), negative predictive value (35.00 %), coincidence (81.82 %), and AUC (0.843). Although acid-fast staining had limitations, its combination with nanopore sequencing improved screening effectiveness.

CONCLUSION

Compared to established diagnostic modalities such as acid-fast staining, mycobacterial solid culture, Xpert MTB/RIF, and DNA detection, third-generation nanopore sequencing technology demonstrates a significant improvement in sensitivity for detecting suspected pulmonary tuberculosis in diabetic patients. Notably, the combined application of nanopore sequencing with Xpert testing offers a further enhancement in diagnostic accuracy.

A metagenomic study of the gut microbiome in PTB'S disease

BACKGROUND

There is an abundant link between the gut microbiota and human health and it plays a critical role in the clinic. It is recognized that microbial dysregulation contributes to the pathogenesis of tuberculosis (TB), but the underlying mechanisms remain unclear. In this study, we investigated the association of gut microbiome composition with TB as well as its possible roles in the development of this disease.

METHODS

Fecal samples were collected from 10 TB patients and 20 healthy control samples. DNA extracted from fecal samples was subjected to 16S rDNA gene sequencing analysis on the Illumina MiSeq platform.

RESULTS

Compared with healthy control samples, the gut microbiome of patients with TB was characterized by the decreased Alpha diversity. Perhaps, the decrease of microbial diversity which results in microbial dysregulation is the reason for clinical patients with more symptoms. The PTB group showed the most unique microbiota by higher abundance of Bifidobacteriaceae, Bifidobacteriales, Coriobacteriaceae, Coriobacteriales, Actinobacteria, Caulobacteraceae, Phyllobacteriaceae, Rhizobiales, Burkholderiaceae, Burkholderiaceae. Inflammatory status in PTB patients may be associated with the increased abundance of Clostridia and decreased abundance of Prevotella. We found that the abundance of Solobacterium and Actinobacteria was higher in the patients. There were 4 significant differences (p<0.05) in the two groups which belonged to four metabolic categories, including endocytosis, phosphotransferase system (PTS), toluene degradation, and amoebiasis.

CONCLUSION

We applied the approach of metagenomic sequencing to characterize the features of gut microbiota in PTB patients. The present study provided a detailed analysis of the characterization of the gut microbiota in patients based on the clinic. According to the metagenome analysis, our results indicated that the gut microbiota in PTB patients was significantly different from healthy control samples as characterized by the bacteria and metabolic pathway. The richness of the gut microbiota in patients was revealed. It was hypothesized that the above-mentioned changes of the gut microbiota could exert an impact on the development of PTB through the downstream regulation of the immune status of the host by way of the gut-lung axis.

Diabetes and COVID-19: Mechanism of pneumonia, treatment strategy and vaccine

As of August 5, 2021, there were about 200,000,000 global confirmed patients of COVID-19, with more than 4,250,000 deaths. The COVID-19 disease which is a tremendous public health threat, jumps unpredictably and outbreaks very quickly. The overall mortality rate of COVID-19 infection is 1%-15% but reaches up to 17-38% in older cases with chronic disorders and in intensive care unit (ICU) subjects. Diabetic patients, particularly those whose disease is not well controlled can be more susceptible to COVID-19. Although diabetes was present in 5.3%-42.3% of fatalities from COVID-19, the underlying pathophysiological mechanisms of action of novel coronavirus in diabetic patients are unknown. Based on the elevating of global prevalence, diabetes is the main medical problem associated with COVID-19. It is plausible that diabetes can forecast elevated severity of pneumonia. The mortality of lung infection among diabetes is remarkably higher compared with non-diabetic patients. Mechanisms responsible for severe pneumonia in the diabetic patients as well as treatment of diabetic patients infected with COVID-19 are largely speculative. Hence, this paper will summarize the recent findings related to the mechanisms of pneumonia and treatment strategies in diabetic patients.

Should We Be Concerned about the Association of Diabetes Mellitus and Periodontal Disease in the Risk of Infection by SARS-CoV-2? A Systematic Review and Hypothesis

The objective of this article was to conduct a systematic review of the literature to contrast the existing evidence regarding the relationship between periodontal disease (PD) and diabetes mellitus (DM) with the possibly increased risk of SARS-CoV-2 infection, as well as to establish a hypothesis that explains the ways in which this interaction could take place. A literature search up from 1 January 2020 to 21 March 2021 was conducted in three electronic databases, namely, PubMed, Web of Science, and Scopus, in order to identify studies on periodontal disease alone or in conjunction with diabetes mellitus, reporting any relation with SARS-CoV-2 infection as a primary outcome. Only articles published in the English language were included. Due to the lack of studies, we decided to collect all the theoretical and clinical evidence suggesting a possible biological pathway evidencing the relationship among PD, DM, and SARS-CoV-2 infection. From a total of 29 articles, 12 were included for final review studies (five reviews, two hypotheses, one Special Issue, one perspective, one commentary, one case–control study, and one case report). In addition, this systematic review article hypothesizes the correlation between PD and type 2 diabetes mellitus (T2DM) by expression of angiotensin-converting enzyme 2 (ACE2) in periodontal tissue and the risk of SARS-CoV-2 infection. T2DM is a metabolic disorder characterized by high blood glucose levels resulting from altered insulin secretion or action. Likewise, periodontitis and T2DM are inflammatory disorders with a bidirectional association, and both diseases have a similar immunomodulatory cascade and cytokine profile. ACE2 is a crucial component of the renin–angiotensin system (RAS) and the key factor of entry in the cells by the new SARS-CoV-2. ACE2 is widely distributed in the lung and kidneys, and interestingly has a great distribution in the oral cavity, principally in the tongue and periodontal tissue. ACE2 in periodontal tissue plays a crucial role between health and disease. Moreover, the ACE2/Ang-(1-7)/MasR axis is downregulated in the dysbiotic and inflammatory periodontal environment. Nevertheless, the balance of ACE2 activity is modified in the context of concurrent diabetes, increasing the expression of ACE2 by the uncontrolled glycemia chronic in T2DM. Therefore, the uncontrolled hyperglycemia possibly increases the risk of developing periodontitis and triggering overexpression of ACE2 in periodontal tissue of T2DM patients, with these events potentially being essential to SARS-CoV-2 infection and the development of mild-to-severe form of COVID-19. In this sense, we would like to point out that the need for randomized controlled trials is imperative to support this association.