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Posted in ‘Intestine’, The study found that associations between gut microbiota composition, cytokine levels, and inflammatory markers in patients with COVID-19 suggest that the gut microbiome is involved in the severity of COVID-19 via the modulation of host immune responses.
Researchers also suggest that dysbiosis of the gut microbiota after the disease resolves could contribute to persistent symptoms, also known as “ long COVID, ” highlighting the need to understand how gut microorganisms are involved in inflammation and COVID-19.
The researchers, at the Chinese University of Hong Kong, collected blood and stool samples from 100 patients with COVID-19 between February and May 2020. A total of 274 stool samples were sequenced.
By identifying the microbial species associated with the severity of the disease, they found that F. prausnitziiAnd Bifidobacterium bifidumWere negatively correlated with severity after adjusting for antibiotic use and patient age. The numbers of these bacteria remained low in samples taken for up to 30 days after infected patients cleared the virus from their bodies.
The report states: “The potential role played by gut microorganisms in COVID-19 could allow the use of a microbiome-based risk profile to identify those at risk for severe disease or downstream inflammatory symptoms such as multisystem inflammation and Kawasaki-like disease in children.
“Based on several patients interviewed in this study up to 30 days after SARS-CoV-2 clearing, the gut microbiota is likely to remain significantly altered after recovery from COVID-19. Based on reports according to which a subset of COVID patients recovered -19 experience persistent symptoms such as fatigue, dyspnea, and joint pain, some more than 80 days after the initial onset of symptoms, we speculate that the dysbiotic gut microbiome may be contributing to post-COVID-19 immune system health problems. “
The study
First, the researchers compared the gut microbiota compositions of the first stool samples from each COVID-19 patient (n = 87) with non-COVID-19 subjects (45 female to 33 male, 45.5 ± 17.4 years old) to assess whether the composition of the gut microbiota has changed.
They found that members of the BacteroidetesWere more relatively abundant in patients with COVID-19 compared to non-COVID-19 individuals (mean 23.9% vs 12.8%), whereas ActinobacteriaWere more relatively abundant in non-COVID-19 individuals (26.1% vs. 19.0%).
Without controlling the use of antibiotics, the compositional differences in the gut microbiota of COVID-19 were mainly due to the enrichment of species, including Ruminococcus gnavus, Ruminococcus pairsAnd Bacteroides doreiAnd the exhaustion of Bifidobacterium, Faecalibacterium prausnitziiAnd Rectal eubacterium.
When the effects of antibiotics were examined, the differences between the cohorts were mainly related to the enrichment of taxa such as Parabacteroids, Sutterella wadsworthensisAnd Bacteroides caccaeAnd the exhaustion of Adlercreutzia equolifaciens, Dorea formicigeneransAnd Clostridium leptumIn COVID-19 compared to non-COVID-19, although most of the taxa involved included less than 0.1% mean relative abundance in these samples.
While the overall composition of the gut microbiota was distinct between the 87 COVID-19 and 78 non-COVID-19 subjects, there were no significant differences in species richness and Shannon diversity.
The researchers note that the observational nature of the study means they can’t establish cause and effect, and it’s important to note that the gut microbiome varies widely between populations.
They also say their short follow-up period does not allow extrapolation of gut microbiota makeup to long-term persistent symptoms.
The report states: “Longer follow-up of patients with COVID-19 (3 months to 1 year after virus elimination) is necessary to answer questions related to the duration of gut microbiota dysbiosis after recovery, to the link between microbiota dysbiosis and long-term persistent symptoms; and whether dysbiosis or the enrichment / depletion of specific gut microorganisms predisposes recovered individuals to future health problems. “
Source: Intestine
doi: 10.1136 / gutjnl-2020-323020
“The composition of the gut microbiota reflects the severity of the disease and dysfunctional immune responses in patients with COVID-19”
Siew. CN, et al
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