Altered Microbial Composition of Drug-Sensitive and Drug-Resistant TB Patients Compared with Healthy Volunteers

Diagnosis and insight into the unique lung microbiota of pediatric pulmonary tuberculosis patients by bronchoalveolar lavage using metagenomic next-generation sequencing

Background

Although previous studies have reported the dysregulation of respiratory tract microbiota in infectious diseases, insufficient data exist regarding respiratory microbiota imbalances in the lower respiratory tracts of children with pulmonary tuberculosis (PTB). In this study, we assessed the value of mNGS in the pathogen diagnosis and microbiome analysis of PTB patients using bronchoalveolar lavage fluid (BALF) samples.

Methods

A total of 64 participants, comprising 43 pediatric PTB and 21 pediatric pneumonia patients were recruited in the present study. BALF samples were collected from the above participants. Parallel comparisons between mNGS and conventional microbial test (CMT) pathogen detection were performed. Moreover, the diversity and structure of all 64 patients' lung BALF microbiomes were explored using the mNGS data.

Results

Comparing to the final clinical diagnosis, mNGS in BALF samples produced a sensitivity of 46.51%, which was lower than that of TB-PCR (55.00%) and Xpert (55.00%). The diagnostic efficacy of PTB can be highly enhanced by mNGS combined with TB-PCR (AUC=0.8140, P<0.0001). There were no significant differences in the diversity either between patients with TB and pneumonia. Positive mNGS pathogen results in pediatric PTB patients significantly affect the β-diversity of the pulmonary microbiota. In addition, significant taxonomic differences were found in BALF specimens from patients with PTB and pneumonia, both of which have unique bacterial compositions.

Conclusions

mNGS is valuable in the etiological diagnosis of PTB, and can reveal pulmonary microecological characteristics. For pediatric PTB patients, the mNGS should be implemented early and complementary to CMTs.

Sputum bacterial microbiota signature as a surrogate for predicting disease progression of nontuberculous mycobacterial lung disease

OBJECTIVES

Predicting progression of nontuberculous mycobacterial lung disease (NTM-LD) remains challenging. This study evaluated whether sputum bacterial microbiome diversity can be the biomarker and provide novel insights into related phenotypes and treatment timing.

METHODS

We analyzed 126 sputum microbiomes of 126 patients with newly diagnosed NTM-LD due to Mycobacterium avium complex, M. abscessus complex, and M. kansasii between May 2020 and December 2021. Patients were followed for 2 years to determine their disease progression status. We identified consistently representative genera that differentiated the progressor and nonprogressor by using six methodologies. These genera were used to construct a prediction model using random forest with five-fold cross validation.

RESULTS

Disease progression occurred in 49 (38.6%) patients. Compared with nonprogressors, α-diversity was lower in the progressors. Significant compositional differences existed in the β-diversity between groups (P = 0.001). The prediction model for NTM-LD progression constructed using seven genera (Burkholderia, Pseudomonas, Sphingomonas, Candidatus Saccharibacteria, Phocaeicola, Pelomonas, and Phascolarctobacterium) with significantly differential abundance achieved an area under curve of 0.871.

CONCLUSION

Identification of the composition of sputum bacterial microbiome facilitates prediction of the course of NTM-LD, and maybe used to develop precision treatment involving modulating the respiratory microbiome composition to ameliorate NTM-LD.

The impact of anti-tuberculosis treatment on respiratory tract microbiome in pulmonary tuberculosis

The growing evidence has underscored the significance of interactions between the host and microbiota in respiratory health, presenting a novel perspective on disease management. Yet, comprehension of the respiratory microbiome shifts before and after anti-tuberculosis treatment is limited. This study compares respiratory microbiome profiles in untreated tuberculosis (UTB) and completed TB treatment (CTB) cases with healthy controls, using 16S rRNA sequencing on sputum samples. Significant reduction in sputum microbial alpha diversity was observed in both TB groups when compared to healthy controls (P < 0.05). Beta diversity analysis showed distinct clustering (P < 0.05). Linear discriminant analysis revealed an abundance of potentially pathogenic bacterial genera like Haemophilus, Pseudomonas, and Mycobacterium in the UTB group, while Streptococcus, Rothia, and Neisseria dominated in CTB samples. Healthy sputum microbiomes were enriched with Prevotella, Fusobacterium, Porphyromonadaceae_unclassified,andPeptostreptococcus. Moreover, predicted bacterial functional pathways showed significant differences among the three groups, mainly related to nutrient metabolism. These findings indicated significant microbial dysbiosis in sputum samples recovered from patients with pulmonary TB with an elevated presence of potentially pathogenic bacteria, depletion of beneficial genera, and downregulation of several essential metabolic pathways. Further exploration of respiratory microbiome-based diagnostic biomarkers and their role in targeted treatment strategies in tuberculosis is warranted.

Association of bacteriomes with drug susceptibility in lesions of pulmonary tuberculosis patients

Understanding how the bacteriomes in tuberculous lesions can be influenced by the susceptibility of Mycobacterium tuberculosis (MTB) can provide valuable information for preventing and treating drug resistant tuberculosis (DR-TB). High-throughput 16S rRNA sequencing was employed to analyze the bacteriome in pulmonary TB lesions from 14 patients with DR-TB and 47 patients with drug sensitive tuberculosis (DS-TB), along with 18 normal lung tissues (NT) from 18 lung cancer patients serving as the bacterial baseline. The phylogenetic investigation of communities by reconstruction of unobserved states2 (PICRUSt2) algorithm was utilized to predict bacterial metabolic functions. The major phyla of pulmonary bacteriomes included Proteobacteria, Actinobacteria, Bacteroidetes, Firmicutes and Fusobacteria. Alpha diversity indices, including ACE, Chao1, Shannon and OTU observed, all demonstrated different bacterial communities of DS-TB samples from that of NT samples; while only Shannon indicated difference between DR-TB and NT samples. The analysis of similarity (ANOSIM) showed significantly different bacterial communities within TB lesions compared to NT samples (R = 0.418, p = 0.001). However, difference was not observed between DR-TB and DS-TB samples (ANOSIM, R = 0.069, p = 0.173). The bacterial profiles within each DR-TB individual appeared unique, with no obvious clusters corresponding to drug-resistant phenotypes. Nevertheless, indicator genera identified in DR-TB and DS-TB lesions demonstrated distinctive micro-ecological environments. Most COG functions were enriched in TB lesions, and the most significant one was [J] translation, ribosomal structure and biogenesis. The distinct enrichment patterns of bacterial enzymes in DR-TB and DS-TB lesions suggest that pulmonary bacterial activities can be modulated by the susceptibility of MTB bacilli. This study provides fresh perspectives and strategies for the precise diagnosis and assessment of drug resistance tuberculosis.

The microbiome and the gut-lung axis in tuberculosis: interplay in the course of disease and treatment

Tuberculosis is a chronic infectious disease caused by Mycobacterium tuberculosis (MTB) that remains a significant global health challenge. The extensive use of antibiotics in tuberculosis treatment, disrupts the delicate balance of the microbiota in various organs, including the gastrointestinal and respiratory systems. This gut-lung axis involves dynamic interactions among immune cells, microbiota, and signaling molecules from both organs. The alterations of the microbiome resulting from anti-TB treatment can significantly influence the course of tuberculosis, impacting aspects such as complete healing, reinfection, and relapse. This review aims to provide a comprehensive understanding of the gut-lung axis in the context of tuberculosis, with a specific focus on the impact of anti-TB treatment on the microbiome.

The gut and lung microbiota in pulmonary tuberculosis: susceptibility, function, and new insights into treatment

INTRODUCTION

Tuberculosis (TB) is a chronic infectious disease caused by mycobacterium tuberculosis (Mtb) that poses a major threat to human health.

AREAS COVERED

Herein, we aim to review the alteration of the microbiota in gut and respiratory during TB development, the potential function and mechanisms of microbiota in the pathogenesis of Mtb infection, and the impact of antibiotic treatment on the microbiota. In addition, we discuss the potential new paradigm for the use of microbiota-based treatments such as probiotics and prebiotics in the treatment of TB.

EXPERT OPINION

Studies have shown that trillions of micro-organisms live in the human gut and respiratory tract, acting as gatekeepers in maintaining immune homeostasis and respiratory physiology and playing a beneficial or hostile role in the development of TB. Anti-TB antibiotics may cause microecological imbalances in the gut and respiratory tract, and microbiome-based therapeutics may be a promising strategy for TB treatment. Appropriate probiotics and prebiotics supplementation, along with antimycobacterial treatment, will improve the therapeutic effect of TB treatment and protect the gut and respiratory microbiota from dysbiosis.

The Microbiome as Part of the Contemporary View of Tuberculosis Disease

The study of the microbiome has changed our overall perspective on health and disease. Although studies of the lung microbiome have lagged behind those on the gastrointestinal microbiome, there is now evidence that the lung microbiome is a rich, dynamic ecosystem. Tuberculosis is one of the oldest human diseases, it is primarily a respiratory infectious disease caused by strains from the Mycobacterium tuberculosis Complex. Even today, during the COVID-19 pandemic, it remains one of the principal causes of morbidity and mortality worldwide. Tuberculosis disease manifests itself as a dynamic spectrum that ranges from asymptomatic latent infection to life-threatening active disease. The review aims to provide an overview of the microbiome in the tuberculosis setting, both in patients’ and animal models. We discuss the relevance of the microbiome and its dysbiosis, and how, probably through its interaction with the immune system, it is a significant factor in tuberculosis’s susceptibility, establishment, and severity.