Gut microbiota composition and diversity before, during, and two months after rifamycin-based tuberculosis preventive therapy

Gut Microbiota in Patients with Tuberculosis Associated with Different Drug Exposures of Antituberculosis Drugs

Interindividual variability in drug exposure can significantly influence treatment outcomes and may lead to drug concentration-related side effects during tuberculosis (TB) treatment. Although the gut microbiota is known to affect drug metabolism, its impact on anti-TB drugs has not been thoroughly explored. This study sought to elucidate the relationship between pre-treatment gut microbiota and drug exposure levels among patients with pulmonary TB. Two cohorts were analyzed: a discovery cohort (N = 99) and a validation cohort (N = 32), both comprising patients undergoing anti-TB therapy with rifampicin, isoniazid, pyrazinamide, and ethambutol. The gut microbiota patterns of participants from the discovery cohort and the validation cohort were profiled by 16S rRNA gene sequencing and metagenomics, respectively. Analyses of both cohorts robustly established a positive association between pre-treatment microbial diversity and drug exposure, as well as significant differences in gut microbiota composition across various drug exposure groups. At the species level, Faecalibacterium prausnitzii was positively associated with drug exposure to rifampicin. Moreover, functional analysis revealed that starch and sucrose metabolism and secondary bile acid biosynthesis were more abundant in the high drug exposure group. To identify biomarkers capable of stratifying patients based on their drug exposure levels, 11 taxa, represented by Faecalibacterium, were selected in the discovery cohort (AUC = 0.992) and were confirmed in the validation cohort with high predictive accuracy (AUC = 0.894). This study demonstrated a correlation between microbial dysbiosis and reduced exposure to anti-TB medications. Optimizing treatment by regulating gut microbiota to improve drug exposure levels requires further validation through larger scale multicenter clinical trials.

The association between the gut microbiome and antituberculosis drug-induced liver injury

Background

This study aimed to explore the distinct characteristics of the gut microbiota in tuberculosis (TB) patients who experienced liver injury following anti-TB treatment compared with those who did not.

Method

We employed a nested case-control study design, recruiting newly diagnosed pulmonary TB patients at Tangshan Infectious Disease Hospital. Participants were categorized into the Antituberculosis Drug-Induced Liver Injury (ADLI) group and the Non-ADLI group based on the occurrence of liver injury after treatment. Both groups received identical anti-TB regimens. Stool samples were collected from patients who developed liver injury within 2-3 weeks of starting treatment, alongside matched controls during the same timeframe. The samples underwent 16S rDNA sequencing, and clinical data and blood samples were also collected for further analysis. At the same time, we constructed mouse models to explore the effects of different anti-tuberculosis drugs on gut microbiota.

Results

Following anti-TB treatment, we observed a decrease in microbial diversity and significant structural changes in the gut microbiota of TB patients (P < 0.05). At T1, the Non_ADLI_T1 group presented relatively high levels of Phascolarctobacterium, Anaerofustis and Mailhella. In contrast, the ADLI_ T1 group presented elevated levels of Bacteroides, Veillonella, Clavibacter, Corynebacterium, Anaerococcus, Gardnerella, Peptostreptococcus and Lautropia. At T2, the ADLI_T2 group presented increased levels of Enterococcus, Faecalibacterium, unclassified_f__Burkholderiaceae, Cardiobacterium, Ruminococcus_gnavus_group and Tyzzerella_4 than did the Non_ADLI_T2 group. Additionally, the ADLI_T2 group presented decreased levels of Prevotella_9, Akkermansia, Erysipelotrichaceae_UCG-003, Rubrobacter and norank_f__Desulfovibrionaceae than did the Non_ADLI_T2 group. In animal experiments, similar changes to those in the human population were observed in the mouse model compared to the control group. Any single anti-tuberculosis drug or two-drug combination or three-drug combination can cause dysbiosis of the mouse gut microbiota. The signature genera between groups are different and related to the type of anti-tuberculosis drug.

Conclusion

Anti-tuberculosis treatment induces dysbiosis in the gut microbiota of TB patients. Notably, there are significant differences in microbiota characteristics between TB patients with and without liver injury at both onset and during treatment. There are some differences in the characteristics of bacterial flora in liver injury caused by different drugs.

Latent Tuberculosis Infection Is Associated with an Enrichment of Short-Chain Fatty Acid-Producing Bacteria in the Stool of Women Living with HIV

Latent tuberculosis infection (LTBI) is common in people living with HIV (PLHIV) in high-TB-burden settings. Active TB is associated with specific stool taxa; however, little is known about the stool microbiota and LTBI in PLHIV. We characterised the stool microbiota of PLHIV with [interferon-γ release assay (IGRA)- and tuberculin skin test (TST)-positive] or without (IGRA- and TST-negative) LTBI (n = 25 per group). The 16S rRNA DNA sequences were analysed using QIIME2, Dirichlet-Multinomial Mixtures, DESeq2, and PICRUSt2. No α- or β-diversity differences occurred by LTBI status; however, LTBI-positive people were Faecalibacterium-, Blautia-, Gemmiger-, and Bacteroides-enriched and Moryella-, Atopobium-, Corynebacterium-, and Streptococcus-depleted. Inferred metagenome data showed that LTBI-negative-enriched pathways included several metabolite degradation pathways. Stool from LTBI-positive people demonstrated differential taxa abundance based on a quantitative response to antigen stimulation. In LTBI-positive people, older people had different β-diversities than younger people, whereas in LTBI-negative people, no differences occurred across age groups. Amongst female PLHIV, those with LTBI were, vs. those without LTBI, Faecalibacterium-, Blautia-, Gemmiger-, and Bacteriodes-enriched, which are producers of short-chain fatty acids. Taxonomic differences amongst people with LTBI occurred according to quantitative response to antigen stimulation and age. These data enhance our understanding of the microbiome's potential role in LTBI.

Synthesis of narrow-spectrum anti-mycobacterial molecules without effect on the diversity of gut microbiota in mice based on the structure of rifampicin

Rifampicin (RIF) is a broad-spectrum antimicrobial agent that is also a first-line drug for treating tuberculosis (TB). Based on the naphthyl ring structure of RIF this study synthesized 16 narrow-spectrum antimicrobial molecules that were specifically anti-Mycobacterium tuberculosis (Mtb). The most potent candidate was 2-((6-hydroxynaphthalen-2-yl) methylene) hydrazine-1-carbothioamide (compound 3c) with minimum inhibitory concentration (MIC) of 1 μg/mL against Mtb. Synergistic anti-Mtb test indicated that none of the combinations of 3c with the major anti-TB drugs are antagonistic. Consistent with RIF, compound 3c induced large amounts of reactive oxygen radicals (ROS) in the cells of Mtb. The killing kinetics of compound 3c and RIF are very similar. Furthermore, molecular docking showed that compound 3c was able to access the RIF binding pocket of the β subunit of Mtb RNA polymerase (RNAP). Experiments in mice showed that compound 3c increased the variety of intestinal flora in mice, while RIF significantly decreased the diversity of intestinal flora in mice. In addition, compound 3c is non-toxic to animal cells with a selection index (SI) much more than 10. The evidence from this study suggests that the further development of 3c could contribute to the development of novel drug for TB treatment.

Latent tuberculosis infection is associated with an enrichment of short chain fatty acid producing bacteria in the stool of women living with HIV

Background

Latent tuberculosis infection (LTBI) is common in people living with HIV (PLHIV) in high TB burden settings. Active TB is associated with specific stool taxa; however, little is known about the stool microbiota and LTBI, including in PLHIV.

Method

Within a parent study that recruited adult females with HIV from Cape Town, South Africa into predefined age categories (18-25, 35-60 years), we characterised the stool microbiota of those with [interferon-γ release assay (IGRA)- and tuberculin skin test (TST)-positive] or without (IGRA- and TST- negative) LTBI (n=25 per group). 16S rRNA DNA sequences were analysed using QIIME2, Dirichlet Multinomial Mixtures, DESeq2 and PICRUSt2.

Results

No α- or β-diversity differences occurred by LTBI status; however, LTBI-positives were Faecalibacterium-, Blautia-, Gemmiger-, Bacteroides-enriched and Moryella-, Atopobium-, Corynebacterium-, Streptococcus-depleted. Inferred metagenome data showed LTBI-negative-enriched pathways included several involved in methylglyoxal degradation, L-arginine, putrescine, 4-aminobutanoate degradation and L-arginine and ornithine degradation. Stool from LTBI-positives demonstrated differential taxa abundance based on a quantitative response to antigen stimulation (Acidaminococcus-enrichment and Megamonas-, Alistipes-, and Paraprevotella-depletion associated with higher IGRA or TST responses, respectively). In LTBI-positives, older people had different β-diversities than younger people whereas, in LTBI-negatives, no differences occurred across age groups.

Conclusion

Amongst female PLHIV, those with LTBI had, vs. those without LTBI, Faecalibacterium, Blautia, Gemmiger, Bacteriodes-enriched, which are producers of short chain fatty acids. Taxonomic differences amongst people with LTBI occurred according to quantitative response to antigen stimulation and age. These data enhance our understanding of the microbiome's potential role in LTBI.