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Gut Microbiota Composition in COVID-19 Patients
abstract
This abstract is available on the publisher's site.
Access this abstract nowOBJECTIVE
Although COVID-19 is primarily a respiratory illness, there is mounting evidence suggesting that the GI tract is involved in this disease. We investigated whether the gut microbiome is linked to disease severity in patients with COVID-19, and whether perturbations in microbiome composition, if any, resolve with clearance of the SARS-CoV-2 virus.
METHODS
In this two-hospital cohort study, we obtained blood, stool and patient records from 100 patients with laboratory-confirmed SARS-CoV-2 infection. Serial stool samples were collected from 27 of the 100 patients up to 30 days after clearance of SARS-CoV-2. Gut microbiome compositions were characterised by shotgun sequencing total DNA extracted from stools. Concentrations of inflammatory cytokines and blood markers were measured from plasma.
RESULTS
Gut microbiome composition was significantly altered in patients with COVID-19 compared with non-COVID-19 individuals irrespective of whether patients had received medication (p<0.01). Several gut commensals with known immunomodulatory potential such as Faecalibacterium prausnitzii, Eubacterium rectale and bifidobacteria were underrepresented in patients and remained low in samples collected up to 30 days after disease resolution. Moreover, this perturbed composition exhibited stratification with disease severity concordant with elevated concentrations of inflammatory cytokines and blood markers such as C reactive protein, lactate dehydrogenase, aspartate aminotransferase and gamma-glutamyl transferase.
CONCLUSION
Associations between gut microbiota composition, levels of cytokines and inflammatory markers in patients with COVID-19 suggest that the gut microbiome is involved in the magnitude of COVID-19 severity possibly via modulating host immune responses. Furthermore, the gut microbiota dysbiosis after disease resolution could contribute to persistent symptoms, highlighting a need to understand how gut microorganisms are involved in inflammation and COVID-19.
Additional Info
Disclosure statements are available on the authors' profiles:
Gut Microbiota Composition Reflects Disease Severity and Dysfunctional Immune Responses in Patients With COVID-19
BMJ 2021 Jan 11;[EPub Ahead of Print], YK Yeoh, T Zuo, GC Lui, F Zhang, Q Liu, AY Li, AC Chung, CP Cheung, EY Tso, KS Fung, V Chan, L Ling, G Joynt, DS Hui, KM Chow, SSS Ng, TC Li, RW Ng, TC Yip, GL Wong, FK Chan, CK Wong, PK Chan, SC NgFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
Primary Care
COVID severity and the microbiome
The gut microbiome regulates the inflammatory–immune response, and COVID severity is determined largely by excess inflammation. Certain phyla of bacteria are associated with less inflammation, reducing triggering cytokines. This study showed that severe COVID cases had fewer of these anti-inflammatory bacteria.
Serum for inflammatory markers and stool for microbiome composition were collected from COVID (n=100) and non-COVID (n=78) patients from two hospitals in Hong Kong. Stool samples were taken up to 30 days after clearing the virus to see if the microbiome changed.
The microbiome of those with COVID revealed the following:
Fewer bacteria were found that were associated with dampening immune-mediated inflammation, including Faecalibacterium prausnitzii, Eubacterium rectale, and several bifidobacterial species.
The microbiome patterns persisted after clearance of the COVID virus, suggesting a possible correlation with post-COVID symptoms and inflammation.
Inflammatory markers (ESR, CRP, NT pro-BNP, TNF) and disease severity correlated with microbiome composition.
Antibiotics did not improve patient outcomes, and the authors postulate that antibiotic administration in severe cases could worsen inflammation.
I would hope that taking a probiotic with anti-inflammatory phyla of bacteria would help treat COVID; but, as we have learned many times, it is often more complicated. Once the microbiome is established, it is hard to change, and the quality of nutrition influences its growth. If we are lucky enough give a probiotic mixture to repopulate the gut with a less inflammatory microbiome, we will still need to sustain it with a high-fiber, plant-based diet. And supporting this behavior change is always more challenging than taking a pill.