Alterations in the human oral and gut microbiomes and lipidomics in COVID-19Original 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 characterized the oral and gut microbiomes and serum lipids in COVID-19 and tested whether microbial markers could non-invasively diagnose the disease. Tongue-coating and fecal samples were profiled by 16S ribosomal RNA MiSeq sequencing, and serum lipids by ultra-performance liquid chromatography-mass spectrometry. Random forest classifiers were trained on optimal microbial markers, validated across cohorts and regions, and correlations between microbiome and lipids were analyzed.
Who was studied?
The study analyzed 719 human samples from Central and East China: 392 tongue-coating, 172 fecal, and 155 serum samples. Groups included confirmed COVID-19 patients, suspected patients with IgG antibody positivity, recovered patients, and healthy controls collected before October 2019. A cross-regional set of 74 confirmed patients came from Hangzhou. In the discovery cohort, confirmed patients and controls were matched for sex and age, with fever and cough the most common symptoms.
What were the most important findings?
Oral and fecal microbial diversity fell significantly in confirmed patients versus healthy controls (p < 0.001). Butyric-acid-producing bacteria decreased and lipopolysaccharide-producing bacteria increased. An 8-marker oral classifier reached an area under the curve of 98.06% in discovery and 87.24% across regions. A 7-marker fecal classifier reached 99.74%. The classifiers diagnosed IgG-positive suspected patients as COVID-19, with area under the curve of 92.11% (oral) and 98.01% (fecal). Recovery involved 47 depleted and 122 enriched lipid molecules.
What are the greatest implications of this study?
The results suggest oral and fecal microbial signatures could serve as an auxiliary non-invasive diagnostic tool for COVID-19, potentially catching cases missed by RT-PCR. Diagnosing antibody-positive suspected patients as confirmed cases hints that microbial markers may extend testing where nucleic acid results are falsely negative. Shifts in butyrate and lipopolysaccharide producers, plus linked lipid changes during recovery, point to microbiome-metabolite interactions in disease and rehabilitation. The design is observational and needs external validation before clinical use.