The mouth bacteria of severe COVID-19 patients look different

What is it about?

The coronavirus SARS-CoV-2 can be found in saliva, and the lining of the mouth carries the receptors the virus uses to enter cells. We compared the bacteria living in the mouth (oral microbiota) and the inflammatory molecules (cytokines) in saliva and blood of 26 patients with severe COVID-19, not yet treated, and 15 healthy controls. COVID-19 patients had fewer bacterial species and a clearly different community: Prevotella salivae and Veillonella infantium were typical of patients, whereas Neisseria perflava and Rothia mucilaginosa dominated in controls. These two groups of bacteria formed opposite clusters in the bacterial network. Pro-inflammatory cytokines related to COVID-19 were found in both saliva and blood, together with a group of bacteria that seemed able to counteract them. We also developed an index, CytoCOV, that predicted COVID-19 status with high accuracy in this pilot study.

Featured Image

Photo by Marek Studzinski on Unsplash

Photo by Marek Studzinski on Unsplash

Why is it important?

The mouth is both an entry gate and a reservoir for SARS-CoV-2. This pilot study shows that severe COVID-19 is associated with a distinctive oral microbiota linked to local and systemic inflammation, suggesting that oral bacterial communities could serve as biomarkers or even be targeted to reduce local inflammation. Larger studies are needed to confirm these findings.

Perspectives