SARS-CoV-2 infection notoriously impairs respiratory function. Given that the microbiome, or community of microorganisms inhabiting the upper respiratory tract (URT), is involved in regulating respiratory health and immune response, a timely study by Suman Das, Ph.D., and colleagues assessed whether the URT microbiome reflects COVID-19 severity.
The cross-sectional study compared URT microbiome characteristics of 103 individuals assigned to five groups based on COVID-19 severity, ranging from uninfected to ‘very severe’ ICU hospitalized patients.
Reporting in Frontiers in Cellular and Infection Microbiology, the researchers found that as COVID-19 severity increased, so did bacterial load (abundance) and bacterial richness (diversity).
The microbiomes became progressively dissimilar, even within the five COVID-19 groups, while the abundance of Corynebacterium, one species of which can inhibit other disease-causing bacteria and viruses, declined.
These data support the association of SARS-CoV-2 infection with dysbiosis, the disruption of the microbiome, whereby beneficial bacteria decrease, and pathogens can proliferate. While further study is needed, microbiome characterization could serve an outcome predictor for COVID-19.
This work was supported in part by the U.S. Centers for Disease Control and Prevention, and by National Institutes of Health grants AI142321, AI142321, AI154016, AI149262, HL148638, HL146401 and TR002556.