Major alteration of Lung Microbiome and the Host Reaction in critically ill COVID-19 Patients with high viral load

Area of Science:

• Infectious Diseases
• Microbiology
• Immunology

Background:

• COVID-19 patients on mechanical ventilation face increased risk of ventilator-associated pneumonia (VAP).
• The mechanisms driving VAP in this population remain unclear.
• This study investigates lung microbiota and host immune responses in mechanically ventilated COVID-19 patients to understand VAP development.

Approach:

• A prospective cohort study enrolled mechanically ventilated COVID-19 patients.
• Nasal swabs, endotracheal aspirates, and blood samples were collected at baseline and 72 hours post-intubation.
• Analyses included lung microbiome sequencing, plasma cytokine profiling, and metabolomics.

Key Points:

• Significant differences in nasal and pulmonary microbiomes (e.g., *Staphylococcus*, *Enterobacteriaceae*) were associated with VAP.
• VAP patients exhibited higher SARS-CoV-2 viral load, elevated neutralizing antibodies, and reduced specific inflammatory cytokines.
• Metabolomic analysis identified distinct metabolite profiles in VAP and non-VAP patients, suggesting metabolic predispositions.

Conclusions:

• A strong association exists between respiratory microbiome alterations and VAP in COVID-19 patients.
• Elevated SARS-CoV-2 levels and specific metabolic changes contribute to VAP pathogenesis.
• Findings offer novel insights into VAP mechanisms, potentially informing management and prevention strategies.