Disorders of gut microbiota and fecal-serum metabolic patterns are associated with pulmonary tuberculosis and pulmonary tuberculosis comorbid type 2 diabetes mellitusOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study asked how gut bacteria and metabolites differ in pulmonary tuberculosis, with and without type 2 diabetes. Researchers ran a prospective observational study combining three tools. They applied 16S rDNA gene sequencing to stool, plus untargeted metabolomics on frozen stool and serum. The goal was to find shared microbial and metabolic biomarkers. Diversity, taxa, differential metabolites, and KEGG pathways were compared across the three groups, then linked by correlation network analysis.
Who was studied?
The cohort was 39 adults in Hangzhou, China: 13 healthy volunteers, 13 pulmonary tuberculosis patients, and 13 pulmonary tuberculosis patients who also had type 2 diabetes. All tuberculosis and tuberculosis-diabetes patients were newly diagnosed and had received no anti-tuberculosis drugs before sampling. Diabetes patients still had high blood glucose despite insulin. Healthy participants had taken no antibiotics for one year before sampling.
What were the most important findings?
Alpha diversity fell in tuberculosis patients and fell further in tuberculosis-diabetes patients, reaching significance. Diabetes worsened the tuberculosis-driven diversity loss. Firmicutes abundance dropped from 71.32 percent in healthy people to 60.68 percent in tuberculosis and 55.54 percent in tuberculosis-diabetes. The Firmicutes-to-Bacteroidetes ratio rose significantly in the diabetes group. Butyrate-producing families were consistently suppressed. Amino acids including serine, proline, and histidine rose in both patient groups. Fecal metabolomics found thousands of shifted metabolites. Amino acid pathways, notably phenylalanine, tyrosine, and tryptophan biosynthesis, were shared across both patient groups.
What are the greatest implications of this study?
Shared reductions in butyrate-producing genera and shifts in amino acid metabolism could serve as candidate biomarkers for tuberculosis risk in diabetic patients. The findings point to gut dysbiosis as a plausible contributor to heightened tuberculosis susceptibility in diabetes. The authors caution against causal claims. The sample was small, and links between microbes and metabolites need confirmation, for example through fecal transplant experiments.