Microbial dysbiosis is characterized as a process by which a person’s bacteria loses diversity, shifting out-of-balance: normally present bacteria are underrepresented, while normally outcompeted bacteria are present.
- Symptoms described in Long Covid, like fatigue, sleep disturbance, joint pain, anxiety/depression, headache, and diarrhea, have also been correlated with a dysbiosis of the gut microbiome
- Faecal samples with signature of high SARS-CoV-2 infectivity had higher abundances of bacterial species Collinsella aerofaciens, Collinsella tanakaei, Streptococcus infantis, Morganella morganii, and higher functional capacity for nucleotide de novo biosynthesis, amino acid biosynthesis and glycolysis, whereas faecal samples with signature of low-to-none SARS-CoV-2 infectivity had higher abundances of short-chain fatty acid producing bacteria, Parabacteroides merdae, Bacteroides stercoris, Alistipes onderdonkii and Lachnospiraceae bacterium 1_1_57FAA.
- This pilot study provides evidence for active and prolonged ‘quiescent’ GI infection even in the absence of GI manifestations and after recovery from respiratory infection of SARS-CoV-2. Gut microbiota of patients with active SARS-CoV-2 GI infection was characterized by enrichment of opportunistic pathogens, loss of salutary bacteria and increased functional capacity for nucleotide and amino acid biosynthesis and carbohydrate metabolism.
Patients had increased proportions of opportunistic fungal pathogens—Candida albicans, Candida auris, and Aspergillus flavus—compared with the controls.
- In a pilot study, Zuo et al. investigated the changes of the human gut microbiota during the time of hospitalization (Zuo et al., 2020b). Compared to healthy individuals, where Eubacterium, Faecalibacterium prausnitzii, Roseburia, and Lachnospiraceaetaxa are prevalent, the gut microbiome of patients with COVID-19 showed an enrichment of opportunistic pathogens—for example, Clostridium hathewayi, Bacteroides nordii, and Actinomyces viscosus—and, at the same time, depletion of commensals. These changes occurred for both patients that did and did not receive antibiotics.
- Most importantly, gut dysbiosis persists during the COVID-19 disease course, even after clearance/recovery from SARS-CoV-2 infection.
- The baseline fecal abundance of the bacteria Coprobacillus, Clostridium ramosum, and Clostridium hathewayi showed a strong correlation with COVID-19 disease severity.
- In contrast, Alistipes onderdonkii and Faecalibacterium prausnitzii, the later known to have an anti-inflammatory activity, showed an inverse correlation.
- Gut microbial features like the relative abundance of Bacteroides genus, Streptococcus genus, Lactobacillus genus, Ruminococcaceae family, Lachnospiraceae family, and Clostridiales order will drive these biomarkers.
- The fecal metabolome was investigated and showed that 45 fecal metabolites, mainly within the categories of amino acids, fatty acids, and bile acids, can provide a link between the identified core gut microbiota, inflammation, and COVID-19 susceptibility.
Key Players #
- Amy Proal – Polybio