Is Gut Microbiota Dysbiosis a Predictor of Increased Susceptibility to Poor Outcome of COVID-19 Patients? An Update

Abstract

The scientific knowledge already attained regarding the way severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infects human cells and the clinical manifestations and consequences for Coronavirus Disease 2019 (COVID-19) patients, especially the most severe cases, brought gut microbiota into the discussion. It has been suggested that intestinal microflora composition plays a role in this disease because of the following: (i) its relevance to an efficient immune system response; (ii) the fact that 5–10% of the patients present gastrointestinal symptoms; and (iii) because it is modulated by intestinal angiotensin-converting enzyme 2 (ACE2) (which is the virus receptor). In addition, it is known that the most severely affected patients (those who stay longer in hospital, who require intensive care, and who eventually die) are older people with pre-existing cardiovascular, metabolic, renal, and pulmonary diseases, the same people in which the prevalence of gut microflora dysbiosis is higher. The COVID-19 patients presenting poor outcomes are also those in which the immune system’s hyperresponsiveness and a severe inflammatory condition (collectively referred as “cytokine storm”) are particularly evident, and have been associated with impaired microbiota phenotype. In this article, we present the evidence existing thus far that may suggest an association between intestinal microbiota composition and the susceptibility of some patients to progress to severe stages of the disease.

Interrogating the Impact of Intestinal Parasite-Microbiome on Pathogenesis of COVID-19 in Sub-Saharan Africa

“…The microbiome in these patients is predominantly composed of harmful organisms, such as Streptococcus, Rothia, Veilonella, and Actinomyces, and decreased levels of beneficial symbionts, including Agathobacter, Fusicatenibacter, Roseburia, and Ruminococcaceae. In addition, a significant correlation was observed between microbial composition and COVID-19 severity; whereas microbiota that positively correlated with disease severity belonged to harmful organisms, such as Firmicutis, Coprobacillus, and Clostridium spp., beneficial microbiota, including Alistipes ondedonkii and Faecalibacterium prausnitzii negatively correlated with COVID-19 severity (Ferreira et al, 2021).…”

“…Given the recent advent of the SARS-CoV-2 infection, the relationship between COVID-19 severity and microbiome diversity and composition is emerging. Recent reports have demonstrated that gut microbiota composition and diversity is significantly altered in patients with COVID-19 who harbored significantly dysbiotic microbiota composition when compared to healthy individuals (Reviewed in Ferreira et al, 2021). The microbiome in these patients is predominantly composed of harmful organisms, such as Streptococcus, Rothia, Veilonella, and Actinomyces, and decreased levels of beneficial symbionts, including Agathobacter, Fusicatenibacter, Roseburia, and Ruminococcaceae.…”

Nutritional Status and the Critically Ill Patient: Gut Microbiota and Immuno-Nutrition in I.C.U. at the Time of SARS-COV 2 Pandemic

“…On the other hand, Clostridia spp. showed a negative correlation [62]. Interestingly, a strong association was demonstrated between the severity of COVID-19 in the elderly and such bugs and the blood proteomics risk score (PRS).…”

The Role of Dysbiosis in Critically Ill Patients With COVID-19 and Acute Respiratory Distress Syndrome

“…Additionally, lymphopenia may be associated with glucocorticoids treatment (51). Since gut microbiota is one of the key components of the host immune system, and primary responses to infections and other immune insults, lymphopenia due to SARS-CoV-2 infection may interfere and predispose to changes in the normal flora by opportunistic germs (52)(53)(54)(55).…”