Prospectives of novel therapeutic and prophylactic medications based on symbiotic bacterial strains for correction of immune disorders mediated by intestinal microbiota in COVID-19

Recent studies on the role of intestinal microbiota in animals and humans show that the microorganisms are an important determinant of host health, participating in the pathogenesis of various infectious and non-infectious diseases. Currently, the effects of functional gut-lung axis are being actively investigated in the new coronavirus (COVID-19) infection. Gastrointestinal tract may be the point of entry for infection, suggesting involvement of intestinal microbiota in the infectious process. On the one hand, the changes in gut microbiota (dysbiosis) in SARS-CoV-2 patients may be among the factors contributing to development of secondary bacterial infection, sepsis, systemic inflammation and multi-organ failure. On the other hand, impaired gut microbiota contributes to severe clinical course and mortality in patients due to bidirectional coupling of the gut microbiota with immune system via cytokine network. The studies have shown a link between the severity of COVID-19 in patients, cytokine levels, and presence of distinct types of pro- and anti-inflammatory bacteria in the intestinal biotope. Immune abnormalities in COVID-19 patients are also mediated by altered metabolome profile associated with dysbiotic microbiota. The relations between gut microbiota composition, cytokine levels and inflammatory markers suggests that the gut microbiome may influence the progression of coronavirus infection. Therefore, the “symbiotic potential” of normobiotic microbiota may be used to develop prevention and rehabilitation strategies for the patients. This approach may be facilitated by the studies of human-microbiota symbiosis. A number of key mechanisms for studying the integration of Bifidobacteria and Lactobacilli with the host mediated by the immune system, hormones and neurotransmitters are opening new perspectives for medicine, including development of differently targeted probiotic strains for therapeutic and preventative correction of impaired functions within the organism. The studies of microsymbiocenosis, being a vector of associative symbiosis have enabled a technical approach for intermicrobial “friend or foe identification”, where bifidobacteria are used as a diagnostic culture, since “friendly” strains are characterised by synergism (support). By contrary, encountering the “foreign cells” leads to antagonism. This fundamental mechanism may be used for choosing the “host-friendly” bacteria strains eligible for design of a probiotic compositions.