Karen Pendergrass, Standards Team

This narrative review finds that gut dysbiosis is consistently linked to irritable bowel syndrome, yet microbiome-based therapies show only modest, strain-dependent benefit. A meta-analysis of 35 trials showed probiotics lowered symptom persistence (RR 0.79), but overall evidence certainty is graded low to very low.

Across 263 people spanning anorexic to obese, fecal Lactobacillus reuteri rose with body mass index while Methanobrevibacter smithii, Bifidobacterium animalis, and, unexpectedly, Escherichia coli fell. E. coli was newly found to correlate negatively with BMI. Note: this article was later retracted.

Among 209 Ugandans, Schistosoma mansoni infection was linked to greater gut microbial diversity and a distinct profile, with Treponema enriched and Prevotella and Streptococcus depleted. Several infection-associated taxa statistically mediated links between infection and lower cardiovascular risk factors such as LDL cholesterol and blood pressure.

Neonates of mothers with gestational diabetes had lower gut microbiota richness and altered composition persisting through 9 months.

A one-year longitudinal study of 28 Nigerian infants found delivery mode shaped early gut microbiota, while feeding type later determined Bifidobacterium and other taxa profiles.

In 700 Danish children followed from birth, the early-life gut microbiome showed few consistent links to bone health at age 6, though higher Sutterella at 1 year and Escherichia-Shigella at 1 month were each tied to lower bone mineral density.

Blood-derived bacterial extracellular vesicle profiles distinguished pancreatic cancer patients from controls with near-perfect accuracy (AUC up to 1.000).

Found decreased gut microbial diversity in Alzheimer's patients, with lower Firmicutes and Bifidobacterium and higher Bacteroidetes.

A randomized-controlled trial found that saccharin and sucralose, but not aspartame or stevia, impaired human glycemic responses in a microbiome-dependent, person-specific manner.

Found baseline Proteobacteria abundance and later Enterococcaceae or Streptococcaceae dominance predicted infection risk during ALL chemotherapy.

Levodopa-carbidopa intrajejunal gel therapy for Parkinson disease was linked to higher fecal Enterobacteriaceae, Escherichia, and Serratia, and lower Firmicutes and Blautia, than oral levodopa.

Parkinson's disease patients showed reduced anti-inflammatory Lachnospiraceae taxa and altered fecal lipid, vitamin, and amino acid metabolites compared to controls.

A CORDIOPREV analysis of over 1,300 participants found sex-specific gut microbiota shifts in coronary heart disease, pinpointing seven bacterial taxa, including Ruminococcaceae and Bilophila members, as key markers.

Diet predicted the abundance of 92.4 percent of gut microbial species across 10,068 people, with specific food-microbe links like coffee and yogurt tracking consistently over four years.

Gut bacterial diversity fell in pulmonary tuberculosis and fell further when type 2 diabetes was present. The Firmicutes-to-Bacteroidetes ratio rose in tuberculosis patients with diabetes, and butyrate-producing families were consistently suppressed.

Gut Klebsiella and Megasphaera tracked with obesity in African American children while oral Aggregatibacter and Eikenella tracked with obesity in European American children, showing ethnicity-specific microbial obesity signatures.

In a glaucoma rat model, reduced cecal microbial diversity, a raised Firmicutes/Bacteroidetes ratio, and altered bile-acid metabolites correlated with retinal ganglion cell loss.

According to PubMed, this Indian cohort study found Flavonifractor plautii, a flavonoid-degrading bacterium, newly associated with colorectal cancer (DOI: https://doi.org/10.1128/mSystems.00438-19).

In 47 irritable bowel syndrome patients, fecal microbiota differed from healthy controls, with lower Bifidobacterium and Lactobacillus and higher Gram-negative bacteria. Pseudomonas aeruginosa was detected in nearly all patients (97.9 percent) versus one third of controls.

Gut metagenomes of patients with neovascular age-related macular degeneration were enriched in Anaerotruncus, Oscillibacter, Ruminococcus torques, and Eubacterium ventriosum, while Bacteroides eggerthii was enriched in controls, linking the microbiome to this blinding eye disease.

Obese Mexican schoolchildren showed higher Bacteroides eggerthii, while normal-weight children carried more Bacteroides plebeius and Christensenellaceae, both linked to lower phenylalanine levels.

Children with functional constipation showed distinct fecal microbiota, with lower Christensenellaceae, Burkholderiaceae, and Clostridiaceae and higher Tannerellaceae compared to non-constipated peers.

Fecal transfer from telmisartan-treated donor mice transiently lowered weight gain in high-fat-diet recipients and shifted gut microbiota, including Desulfovibrionaceae abundance.

COVID-19 patients showed reduced oral and gut microbial diversity, with fewer butyric-acid-producing and more lipopolysaccharide-producing bacteria. Classifiers built on 8 oral and 7 fecal microbial markers diagnosed COVID-19 with area-under-curve values above 0.87, and diagnosed antibody-positive suspected cases.