Effects of second-line anti-tuberculosis drugs on the intestinal microbiota of patients with rifampicin-resistant tuberculosisOriginal 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 cross-sectional study examined how second-line anti-tuberculosis drugs alter the gut microbiome in patients with rifampicin-resistant tuberculosis (RR-TB). Stool samples were analyzed by shotgun metagenomic sequencing. Researchers compared microbial composition, diversity, differential species, and predicted functions across an untreated control group and patients in the intensive and continuation phases of treatment.
Who was studied?
The cohort was 150 RR-TB patients at Hunan Chest Hospital, China, enrolled from September 2021 to May 2022. Groups were 30 newly diagnosed controls on first-line drugs only, 60 patients at the 6-month intensive phase (average 87 days on second-line drugs), and 60 at the 12-14 month continuation phase (average 373 days). Age, sex, and body mass index did not differ significantly across groups.
What were the most important findings?
Alpha diversity (Shannon, Simpson) did not change, but overall community structure shifted significantly across the three groups (Adonis test, all P below 0.05). The intensive phase enriched 11 potentially pathogenic species, including Escherichia coli (0.0146 to 0.0448), Klebsiella pneumoniae, Citrobacter freundii, Morganella morganii, Shigella sonnei, and Salmonella enterica. Beneficial taxa fell, including Prevotella copri and Rothia mucilaginosa. Amino acid biosynthesis of phenylalanine, tyrosine, and tryptophan was inhibited, while degradation of lysine and fatty acids increased.
What are the greatest implications of this study?
The findings suggest second-line TB treatment, especially the intensive phase, drives gut dysbiosis by expanding Enterobacteriaceae pathogens and reducing short-chain fatty acid producers. Because these microbes and metabolites affect anti-TB immunity, the dysbiosis could theoretically hinder recovery. Controls had already received first-line drugs, and no untreated or healthy comparison group existed, so the isolated effect of second-line drugs cannot be fully separated.