Trust your gut

New Research shows benefits of gut bacteria in fighting COVID

This is the title of the new medical research article:

Lost microbes of COVID-19: Bifidobacterium, Faecalibacterium depletion and decreased microbiome diversity associated with SARS-CoV-2 infection severity.

Here are key parts of the article:

Objective The study objective was to compare gut microbiome diversity and composition in SARS-CoV-2 PCR-positive patients whose symptoms ranged from asymptomatic to severe versus PCR-negative exposed controls.

Design Using a cross-sectional design, we performed shotgun next-generation sequencing on stool samples to evaluate gut microbiome composition and diversity in both patients with SARS-CoV-2 PCR-confirmed infections, which had presented to Ventura Clinical Trials for care from March 2020 through October 2021 and SARS-CoV-2 PCR-negative exposed controls. Patients were classified as being asymptomatic or having mild, moderate or severe symptoms based on National Institute of Health criteria. Exposed controls were individuals with prolonged or repeated close contact with patients with SARS-CoV-2 infection or their samples, for example, household members of patients or frontline healthcare workers. Microbiome diversity and composition were compared between patients and exposed controls at all taxonomic levels.

Results Compared with controls (n=20), severely symptomatic SARS-CoV-2-infected patients (n=28) had significantly less bacterial diversity (Shannon Index, p=0.0499; Simpson Index, p=0.0581), and positive patients overall had lower relative abundances of Bifidobacterium (p<0.0001), Faecalibacterium (p=0.0077) and Roseburium (p=0.0327), while having increased Bacteroides (p=0.0075). Interestingly, there was an inverse association between disease severity and abundance of the same bacteria.

Conclusion We hypothesise that low bacterial diversity and depletion of Bifidobacterium genera either before or after infection led to reduced proimmune function, thereby allowing SARS-CoV-2 infection to become symptomatic. This particular dysbiosis pattern may be a susceptibility marker for symptomatic severity from SARS-CoV-2 infection and may be amenable to preinfection, intrainfection or postinfection intervention.

Summary box

What is already known about this subject?

• The gut microbiome is intrinsically related to host immune response (eg, inflammation, Th1 vs Th2) and susceptibility to infection.

What are the new findings?

• Patients with SARS-CoV-2 infections possess significantly less bacterial diversity, lower abundance of Bifidobacterium and Faecalibacterium and increased abundance of Bacteroides at the genus level compared with SARS-CoV-2-exposed controls. There are inverse associations between disease severity and the Shannon and Simpson diversity indices and also with Bifidobacterium and Faecalibacterium abundance. There is also a direct association between severity and Bacteroides abundance.

How might it impact on clinical practice in the foreseeable future?

• Boosting of Bifidobacterium or Faecalibacterium through probiotic supplementation or faecal microbiota transplant is worthy of exploration in the management of patients with acute severe disease or protracted infection. If the changes that we document precede SARS-CoV-2 infection in those who are most severely affected, this therapeutic approach may be of particular interest. Conversely, if the reduction follows infection, then repopulation of the gut microbiome may reduce long-term effects related to gut microbiome composition changes with SARS-CoV-2 infection.

Bottom line: Taking a broad range of probiotics can be part of a healthy lifestyle that improves immunity and defends against COVID. Gut bacteria may be a positive approach to long COVID problems.