Altered oral and gut microbiota and its association with SARS-CoV-2 viral load in COVID-19 patients during hospitalizationOriginal 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 SARS-CoV-2 infection reshapes the oral and gut microbiome during hospitalization. Researchers profiled the microbiome before and after viral clearance and linked bacterial changes to viral load. They sequenced the V3-V4 region of the bacterial 16S rRNA gene from throat swabs and fecal samples. Viral load was measured by real-time RT-PCR targeting the E and N genes. Differential taxa were identified with LEfSe and validated with MaAsLin2, adjusting for age, sex, and antibiotic use.
Who was studied?
The cohort was 53 hospitalized COVID-19 patients and 76 sex- and age-matched healthy individuals in Guangdong, China. Patients were sampled repeatedly across their hospital stay. Investigators collected 140 throat swabs and 81 fecal samples from patients, plus 44 throat swabs and 32 fecal samples from controls. Patients were split into non-severe and severe groups. About 67.9 percent received antibiotics, which was modeled as a confounder.
What were the most important findings?
Both oral and gut microbiomes showed reduced diversity and distinct community structure in patients versus controls. Severe patients had lower diversity than non-severe patients. Granulicatella and Rothia mucilaginosa, normally respiratory-tract bacteria, were elevated in both oral and gut samples of patients. Rothia further tracked with disease severity in feces. Seventeen oral and 17 gut taxa differed significantly. In the oral cavity, several periodontitis- and bacteremia-associated genera increased while commensal diversity fell.
What are the greatest implications of this study?
The findings suggest SARS-CoV-2 infection is accompanied by broad oral and gut dysbiosis that partly recovers as the virus clears. The oral microbiome appeared more strongly disturbed than the gut. Enrichment of opportunistic respiratory bacteria points to a possible link with secondary bacterial infection. This supports attention to oral care in hospitalized patients. Because the design is observational, these associations do not establish that microbiome shifts cause worse outcomes.