Intestinal microbiota disruption limits the isoniazid mediated clearance of Mycobacterium tuberculosis in mice

The characteristics of the gut microbiota in patients with pulmonary tuberculosis: A systematic review

Increasing evidence has indicated dysbiosis of the gut microbiota in patients with pulmonary tuberculosis (PTB). However, the change in the intestinal microbiota varies between different studies. This systematic review was conducted to investigate the characteristics of the gut microbiota in PTB patients. The MBASE, MEDLINE, Web of Science, and Cochrane Library electronic databases were systematically searched, and the quality of the retrieved studies was evaluated using the Newcastle-Ottawa scale. A total of 12 studies were finally included in the systematic review. Compared with healthy controls, the index reflecting α-diversity including the richness and/or diversity index decreased in 6 studies, while β-diversity presented significant differences in PTB patients in 10 studies. Although the specific gut microbiota alterations were inconsistent, short-chain fatty acid-producing bacteria (including Lachnospiraceae, Ruminococcus, Blautia, Dorea, and Faecalibacterium), bacteria associated with an inflammatory state (e.g., Prevotellaceae and Prevotella), and beneficial bacteria (e.g., Bifidobacteriaceae and Bifidobacterium) were commonly noted. Our systematic review identifies key evidence for gut microbiota alterations in PTB patients, in comparison with healthy controls; however, no consistent conclusion could be drawn, due to the inconsistent results and heterogeneous methodologies of the enrolled studies. Therefore, more well-designed research with standard methodologies and large sample sizes is required.

Role of Gut Microecology in the Pathogenesis of Drug-Induced Liver Injury and Emerging Therapeutic Strategies

Drug-induced liver injury (DILI) is a common clinical pharmacogenic disease. In the United States and Europe, DILI is the most common cause of acute liver failure. Drugs can cause hepatic damage either directly through inherent hepatotoxic properties or indirectly by inducing oxidative stress, immune responses, and inflammatory processes. These pathways can culminate in hepatocyte necrosis. The role of the gut microecology in human health and diseases is well recognized. Recent studies have revealed that the imbalance in the gut microecology is closely related to the occurrence and development of DILI. The gut microecology plays an important role in liver injury caused by different drugs. Recent research has revealed significant changes in the composition, relative abundance, and distribution of gut microbiota in both patients and animal models with DILI. Imbalance in the gut microecology causes intestinal barrier destruction and microorganism translocation; the alteration in microbial metabolites may initiate or aggravate DILI, and regulation and control of intestinal microbiota can effectively mitigate drug-induced liver injury. In this paper, we provide an overview on the present knowledge of the mechanisms by which DILI occurs, the common drugs that cause DILI, the gut microbiota and gut barrier composition, and the effects of the gut microbiota and gut barrier on DILI, emphasizing the contribution of the gut microecology to DILI.

Excess fermentation and lactic acidosis as detrimental functions of the gut microbes in treatment-naive TB patients

Introduction

The link between gut microbiota and host immunity motivated numerous studies of the gut microbiome in tuberculosis (TB) patients. However, these studies did not explore the metabolic capacity of the gut community, which is a key axis of impact on the host's immunity.

Methods

We used deep sequencing of fecal samples from 23 treatment-naive TB patients and 48 healthy donors to reconstruct the gut microbiome's metabolic capacity and strain/species-level content.

Results

We show that the systematic depletion of the commensal flora of the large intestine, Bacteroidetes, and an increase in Actinobacteria, Firmicutes, and Proteobacteria such as Streptococcaceae, Erysipelotrichaceae, Lachnospiraceae, and Enterobacteriaceae explains the strong taxonomic divergence of the gut community in TB patients. The cumulative expansion of diverse disease-associated pathobionts in patients reached 1/4 of the total gut microbiota, suggesting a heavy toll on host immunity along with MTB infection. Reconstruction of metabolic pathways showed that the microbial community in patients shifted toward rapid growth using glycolysis and excess fermentation to produce acetate and lactate. Higher glucose availability in the intestine likely drives fermentation to lactate and growth, causing acidosis and endotoxemia.

Discussion

Excessive fermentation and lactic acidosis likely characterize TB patients' disturbed gut microbiomes. Since lactic acidosis strongly suppresses the normal gut flora, directly interferes with macrophage function, and is linked to mortality in TB patients, our findings highlight gut lactate acidosis as a novel research focus. If confirmed, gut acidosis may be a novel potential host-directed treatment target to augment traditional TB treatment.

Alterations in the intestinal microbiota associated with active tuberculosis and latent tuberculosis infection

Objectives

To study the characteristics of intestinal microbiota at different stages of Mycobacterium tuberculosis infection.

Methods

Fecal samples of 19 active tuberculosis (ATB) patients, 21 latent tuberculosis infection (LTBI) individuals, and 20 healthy controls (HC) were collected. Gut microbiota of all the participants were analyzed by 16S rDNA sequencing. Clinical information of ATB patients was also collected and analyzed.

Results

Both ATB and LTBI groups showed significant decreases in microbial diversity and decline of Clostridia. For ATB patients, bacteria within phylum Proteobacteria increased. While for LTBI individuals, genera Prevotella and Rosburia enriched. The abundance of Faecalibacterium, Clostridia and Gammaproteobacteria has the potential to diagnose ATB, with the area under the curve (AUC) of 0.808, 0.784 and 0.717. And Prevotella and Rosburia has the potential to diagnose LTBI, with the AUC of 0.689 and 0.689. Notably, in ATB patients, the relative abundance of Blautia was negatively correlated with the proportions of peripheral T cells and CD8+T cells. And serum direct bilirubin was positively correlated with Bacteroidales, while negatively correlated with Clostridiales in ATB patients.

Conclusions

The specifically changed bacteria are promising markers for ATB and LTBI diagnosis. Some gut bacteria contribute to anti-MTB immunity through interactions with T cells and bilirubin.

Metabolic and Immune Consequences of Antibiotic Related Microbiome Alterations during first-line Tuberculosis Treatment in Bamako, Mali

Background

Tuberculosis (TB) infection is known to lead to the unbalance of the gut microbiota and act synergistically on the decline of the host immune response, when untreated. Moreover, previous work has found a correlation between dysbiosis in the gut microbiota composition and the use of antibiotics. However, there is a need for an in-depth understanding of the metabolic and immune consequences of antibiotic-related microbiome alterations during first-line TB treatment.

Methods

In a longitudinal cohort study, which included TB-infected cohorts and healthy individuals (control group), we studied the anti-TB-related changes in the gut microbiota composition and related functional consequences. Sputum, whole blood and stool samples were collected from participants at four time-points including before (Month-0), during (Month-2), at the end of drug treatment (Month-6) and 9 months after treatment (Month-15). Controls were sampled at inclusion and Month-6. We analyzed the microbiota composition and microbial functional pathways with shotgun metagenomics, analyzed the blood metabolomics using high-performance liquid chromatography (HPLC), and measured the levels of metabolites and cytokines with cytometric bead array.

Results

We found that the gut microbiota of patients infected with TB was different from that of the healthy controls. The gut microbiota became similar to healthy controls after treatment but was still significantly different after 6 months treatment and at the follow up 9 months after treatment. Our data also showed disturbance in the plasma metabolites such as tryptophan and tricarboxylic acids components of patients during TB treatment. Levels of IL-4, IL-6, IL-10, and IFN-γ decreased during treatment and levels were maintained after treatment completion, while IL-17A known to have a strong link with the gut microbiota was highly expressed during treatment period and longer than the 9-month post treatment completion. We found that some fatty acids were negatively correlated with the abundance of taxa. For example, Roseburia, Megasphaera, and alpha proteobacterium HIMB5 species were negatively correlated (rho = -0.6) with the quinolinate production.

Conclusion

Changes in the composition and function of gut microbiota was observed in TB patients before and after treatment compared to healthy controls. The differences persisted at nine months after treatment completion. Alterations in some bacterial taxa were correlated to the changes in metabolite levels in peripheral blood, thus the altered microbial community might lead to changes in immune status that influence the disease outcome and future resistance to infections.

The gut microbiome: A line of defense against tuberculosis development

The tuberculosis (TB) burden remains a significant global public health concern, especially in less developed countries. While pulmonary tuberculosis (PTB) is the most common form of the disease, extrapulmonary tuberculosis, particularly intestinal TB (ITB), which is mostly secondary to PTB, is also a significant issue. With the development of sequencing technologies, recent studies have investigated the potential role of the gut microbiome in TB development. In this review, we summarized studies investigating the gut microbiome in both PTB and ITB patients (secondary to PTB) compared with healthy controls. Both PTB and ITB patients show reduced gut microbiome diversity characterized by reduced Firmicutes and elevated opportunistic pathogens colonization; Bacteroides and Prevotella were reported with opposite alteration in PTB and ITB patients. The alteration reported in TB patients may lead to a disequilibrium in metabolites such as short-chain fatty acid (SCFA) production, which may recast the lung microbiome and immunity via the "gut-lung axis". These findings may also shed light on the colonization of Mycobacterium tuberculosis in the gastrointestinal tract and the development of ITB in PTB patients. The findings highlight the crucial role of the gut microbiome in TB, particularly in ITB development, and suggest that probiotics and postbiotics might be useful supplements in shaping a balanced gut microbiome during TB treatment.

Effects of rearing system and antibiotic treatment on immune function, gut microbiota and metabolites of broiler chickens

BACKGROUND

In China, cage systems with a high space utilization have gradually replaced ground litter systems, but the disease incidence of chickens in cages is higher. Broilers in the ground litter pens may be stimulated by more environmental microbes during the growth process and show strong immune function and status, but knowledge of which microbes and their metabolites play an immunomodulatory role is still limited. This study aimed to explore the differences and correlations in the immune function, gut microbiota and metabolites and the importance of gut microbiota of broilers raised in cages and ground litter pens.

METHODS

The experiment involved a 2 × 2 factorial arrangement, with rearing systems (cages or ground litter pens) and antibiotic treatment (with or without broad-spectrum antibiotics in drinking water) as factors.

RESULTS

The results showed that, compared with the cage group, the ground litter broilers had stronger nonspecific immune function (Macrophages% and NO in blood), humoral immune function (IgG in blood, LPS stimulation index in ileum) and cellular immune function (T%, Tc%, ConA stimulation index and cytokines in blood). Antibiotic (ABX) treatment significantly reduced nonspecific immune function (Macrophages% and NO in blood, iNOS and Mucin2 mRNA expression in ileum), humoral immune function (IgG in blood and sIgA in ileum) and cellular immune function (T% and cytokines in blood, Th and Tc ratio, TLRs and cytokines mRNA expression in ileum). Furthermore, the ground litter broilers had higher α diversity of microbiota in ileum. The relative abundance of Staphylococcus, Jeotgalicoccus, Jeotgalibaca and Pediococcus in the ileum of ground litter broilers were higher. ABX treatment significantly reduced the α diversity of ileal microbiota, with less Chloroplast and Mitochondria. In addition, the levels of acetic acid, isobutyric acid, kynurenic acid and allolithocholic acid in the ileum of ground litter broilers were higher. Spearman correlation analysis showed that Jeotgalibaca, Pediococcus, acetic acid, kynurenic acid and allolithocholic acid were related to the immune function.

CONCLUSIONS

There were more potential pathogens, litter breeding bacteria, short-chain fatty acids, kynurenine, allolithocholic acid and tryptophan metabolites in the ileum of broilers in ground litter pens, which may be the reason for its stronger immune function and status.

Antimicrobial peptides: Sustainable application informed by evolutionary constraints

The proliferation and global expansion of multidrug-resistant (MDR) bacteria have deepened the need to develop novel antimicrobials. Antimicrobial peptides (AMPs) are regarded as promising antibacterial agents because of their broad-spectrum antibacterial activity and multifaceted mechanisms of action with non-specific targets. However, if AMPs are to be applied sustainably, knowledge of how they induce resistance in pathogenic bacteria must be mastered to avoid repeating the traditional antibiotic resistance mistakes currently faced. Furthermore, the evolutionary constraints on the acquisition of AMP resistance by microorganisms in the natural environment, such as functional compatibility and fitness trade-offs, inform the translational application of AMPs. Consequently, the shortcut to achieve sustainable utilization of AMPs is to uncover the evolutionary constraints of bacteria on AMP resistance in nature and find the tricks to exploit these constraints, such as applying AMP cocktails to minimize the efficacy of selection for resistance or combining nanomaterials to maximize the costs of AMP resistance. Altogether, this review dissects the benefits, challenges, and opportunities of utilizing AMPs against disease-causing bacteria, and highlights the use of AMP cocktails or nanomaterials to proactively address potential AMP resistance crises in the future.

Antituberculosis Therapy and Gut Microbiota: Review of Potential Host Microbiota Directed-Therapies

Tuberculosis (TB) remains a major public health concern with millions of deaths every year. The overlap with HIV infections, long treatment duration, and the emergence of drug resistance are significant obstacles to the control of the disease. Indeed, the standard first-line regimen TB treatment takes at least six months and even longer for the second-line therapy, resulting in relapses, drug resistance and re-infections. Many recent reports have also shown prolonged and significant damage of the gut microbial community (dysbiosis) from anti-TB drugs that can detrimentally persist several months after the cessation of treatment and could lead to the impairment of the immune response, and thus re-infections and drug resistance. A proposed strategy for shortening the treatment duration is thus to apply corrective measures to the dysbiosis for a faster bacterial clearance and a better treatment outcome. In this review, we will study the role of the gut microbiota in both TB infection and treatment, and its potential link with treatment duration. We will also discuss, the new concept of "Host Microbiota Directed-Therapies (HMDT)" as a potential adjunctive strategy to improve the treatment effectiveness, reduce its duration and or prevent relapses. These strategies include the use of probiotics, prebiotics, gut microbiota transfer, and other strategies. Application of this innovative solution could lead to HMDT as an adjunctive tool to shorten TB treatment, which will have enormous public health impacts for the End TB Strategy worldwide.

Gut Mycobiota Dysbiosis in Pulmonary Tuberculosis Patients Undergoing Anti-Tuberculosis Treatment

Patients with pulmonary tuberculosis (TB) undergoing anti-tuberculosis (anti-TB) treatment were previously reported to present gut bacterial microbiota dysbiosis, but the role of the mycobiota has not been reported. Here, we conducted a follow-up study of 29 naive TB patients who received first-line anti-TB drug treatment; we collected their fecal samples at different time points, as well as 22 fecal samples from healthy subjects. Fungal ITS2 and bacterial 16S rRNA amplicon sequencing were used to analyze the effects of active TB and anti-TB treatment on the gut microbiota. We found that naive TB patients had bacterial and fungal dysbiosis with altered community composition and a decreased density of the transkingdom correlation network. Anti-TB drug treatment significantly decreased the diversity of bacteria and fungi with altered composition. Notably, we observed that the abundance of Purpureocillium lilacinum tended to decrease and Nakaseomyces spp. tended to increase in the anti-TB treatment, and all of them had increased proportions in the three TB groups compared with healthy subjects. We found that the fungal-bacterial transkingdom network was severely altered in TB patients after 2 months of treatment, and new fungal-enriched connections that were not observed in other groups after 6 months of treatment. This study provides the first detailed analysis of dysbiosis of the gut mycobiota due to active TB and anti-TB treatment. The results suggest that fungi play an important role in the balance of the gut microbiota and may be associated with the progression of TB, influencing the microbiota and immunity homeostasis in those receiving anti-TB treatment.

IMPORTANCE Numerous studies have shown that the gut bacterial microbiota is altered in active TB patients and that anti-TB drugs have profound and long-term impacts. However, as an integral part of the microbiota, fungi have rarely been studied. The need to investigate both the bacterial and fungal microbiota, as well as the relationship between them is apparent. The significance of our study is in our examination of the changes in the bacterial and fungal microbiota simultaneously in both active TB and patients receiving anti-TB treatment. We found that fungi play an important role in the bacterial-fungal transkingdom network, especially during the anti-TB therapy. These findings underscore the importance of fungi in gut microbiota dysbiosis during active TB and anti-TB treatment processes. In addition, our findings suggest it is meaningful to research potential adjunctive therapies that reduce fungal expansion and increase commensal bacterial abundance after anti-TB treatment, which would help the recovery of TB patients.

THE INTESTINAL COMMENSAL, Bacteroides fragilis, MODULATES HOST RESPONSES TO VIRAL INFECTION AND THERAPY: LESSONS FOR EXPLORATION DURING Mycobacterium tuberculosis INFECTION

The gut microbiota has emerged as a critical player in host health. Bacteroides fragilis is a prominent member of the gut microbiota within the phyla Bacteroidetes. This commensal bacterium produces unique capsular polysaccharides processed by antigen-presenting cells and activates CD4⁺ T cells to secrete inflammatory cytokines. Indeed, due to their immunomodulatory functions, B. fragilis and its capsular polysaccharide-A (PSA) are arguably the most explored single commensal microbiota/symbiotic factor. B. fragilis/PSA has been shown to protect against colitis, encephalomyelitis, colorectal cancer, pulmonary inflammation, and asthma. Here, we review (1) recent data on the immunomodulatory role of B. fragilis/PSA during viral infections and therapy, (2) B. fragilis PSA's dual ability to mediate pro-and anti-inflammatory processes, and the potential for exploring this unique characteristic during intracellular bacterial infections such as with Mycobacterium tuberculosis (3) discuss the protective roles of single commensal-derived probiotic species including B. fragilis in lung inflammation and respiratory infections that may provide essential cues for possible exploration of microbiota based/augmented therapies in tuberculosis (TB). Available data on the relationship between B. fragilis/PSA, the immune system, and disease suggest clinical relevance for developing B. fragilis into a next-generation probiotic or, possibly, the engineering of PSA into a potent carbohydrate-based vaccine.

Microbiota and Tuberculosis: A Potential Role of Probiotics, and Postbiotics

Tuberculosis (TB), caused by Mycobacterium tuberculosis attacking the lungs and other organs, is one of the most common infectious disease worldwide. According to the WHO's 2020 report, a quarter of the world's population were infected with M. tuberculosis, and ~1.4 million people died of TB. Therefore, TB is a significant public health concern, which requires cost-effective strategies for prevention and treatment. The microbiota has been considered as a “forgotten organ” and a complex dynamic ecosystem, which plays a significant role in many physiological processes, and its dysbiosis is closely associated with infectious disease. Recently, a few studies have indicated associations between TB and microbiota. This review summarizes studies concerning the alterations of the gut and respiratory microbiota in TB, and their relationship with host susceptibility to M. tuberculosis infection, indicating that microbiota signatures in different stages in TB progression could be considered as biomarkers for TB diagnosis and control. In addition, the potential role of probiotics and postbiotics in TB treatment was discussed.

Therapeutic effect of an anti-tuberculosis agent, isoniazid, and its nano-isoform in ulcerative colitis

BACKGROUND

Isoniazid (INH) is well known as a first-line anti-tuberculosis, while some studies demonstrate that it has anti-inflammatory activity via a different mechanism such as inhibitionthe production of IL-1, ROS, activation of PPARγ expression, inhibition of the transcriptional regulatory activity of NF-κB and AP-1. The aim of this study, investigate the anti-inflammatory effect of INH and INH combined with Sulfasalazine-loaded nanoparticles (NPs) in the ulcerative colitis mouse model.

METHODS

To investigate the anti-inflammatory effect of INH and NPs in the ulcerative colitis mice model, we evaluated the effect of INH clinical symptoms and colonic mucosal histology in colitis.

RESULT

The present study demonstrates that combination therapy of INH with sulfasalazine as well as NPs reduces the symptom of ulcerative colitis and improved disease activity index include body lose weight, diarrhea, rectal bleeding, colonic length, spleen weight, and colon histopathological score in DSS-induced colitis mice model.

CONCLUSION

Our results suggest that the nanoforms of INH with sulfasalazine enhances the therapeutic effect of the drugs in the treatment of ulcerative colitis.