Association of SARS- COV-2 Infection with Lung Microbial Community

Association of SARS- COV-2 Infection with Lung Microbial Community
Fatemeh Akbarian,^1,* Marziye Poornabi,² Fatemeh Tohidi,³
1. Genetics Department, Ale-Taha institute of Higher Education
2. Genetics Department, Ale-Taha institute of Higher Education
3. Genetics Department, Ale-Taha institute of Higher Education
Introduction: Coronavirus disease 2019 (COVID-19) is a contagious disease, caused by SARS-CoV-2 virus. SARS-CoV-2 virus occupies the lung and leads to COVID-19 disease, which has been suggested to be affected by the lung microbiome. The biopsies of lung from dead patients infected by COVID-19 show that the mortality of COVID-19 are correlated with bacterial and fungal contamination. The most bacterial genera were Acinetobacter, Chryseobacterium, Burkholderia, Brevundimonas, Sphingobium, and Enterobacteriaceae, whereas the most common fungal genera was Cutaneotrichosporon. Moreover, the microbiome of the gut is changed in COVID-19 patients, influencing both the immunity and severity of the disease.
Methods: Many studies show a potential role for the interaction of the microbiota (both gut and lung) and host in regulating the pathogenesis of several important lung diseases. Acute respiratory distress syndrome (ARDS) is one of the general and extreme symptoms of COVID-19, where the gut- associated bacteria is enriched in the lung microbiome. Consequently, the bacterial displacement is facilitated by the highly penetrable capillary of alveolus, through the highly penetrable colon wall to the lung. Thus the lung becomes susceptible to opportunistic bacterial infections, leading to inﬂammation, infection and acute pulmonary damage. Furthermore, pneumonia is accompanied with microbiome alteration, where the microbial density increases and its diversity decreases. Bacteria, virus, fungi or protozoans are associated with pneumonia. Microbial dysbiosis has been shown in both COVID-19 and community-acquired pneumonia, due to the existing pathogenic and commensal bacteria. The pulmonary disease is also actuated by microbial dysbiosis of the lung and it might be foregoing by intestinal dysbiosis. The growth of some bacteria is particularly increasing in SARS-CoV-2 infection, leading to secondary pneumonia. Therefore Lung Microbial Community is a serious factor in making antiviral response and influencing the consequence of COVID-19 ARDS.
Results: Bacteriotherapy and using of probiotics could represent a complementary resource for the prevention and restoration of SARS-CoV-2 intestinal mucosa damage through the modulation of gut- lung axis microbiota and decreasing related inflammation. For example, after a respiratory infection, the lactic acid producing bacteria play part in enhancing the antiviral immune response along with increasing natural killer cell activity, whereas the production of pro-inflammatory cytokines are reduced. An effective interaction in constructing an immune response in the lung is also observed between COVID-19 disease and probiotics, particularly Bifdobacteria and Lactobacilli, namely L. gasseri. Veillonella spp. and Prevotella spp. . In addition, the attendance of pathogenic bacteria and probiotics could increase the coronaviruses angiotensin 2 receptor (ACE2). Alteration of microbiota plays a role in down- regulation of intestinal ACE, which can lead to intestinal susceptibility and inflammation. Interestingly, lung microbiome pathways are notable in COVID-19 patients, as their changes are observed to be correlated with enhancements in energy metabolism, metabolism of cofactors and vitamins, purine- related to one-carbon metabolism, nucleotide metabolism, and drug metabolism and also with reduction in amino acid and carbohydrate metabolism. Recently, the Broncho- alveolar lavage fluid sample of COVID-19 patients indicated significant alteration in eighteen metabolic pathways.
Conclusion: Therefore, further analysis is valuable to find therapeutic solutions based on the impact of the lung microbiome on the process of COVID-19 disease. Also, we suggest investigation of major microbiota associated with the previously mentioned metabolic pathways, in order to find effective probiotics for reducing susceptibility to COVID-19 or disease severity.
Keywords: Microbial community (microbiota); COVID-19; Respiratory infection; Lung