Could daily changes in respiratory microbiota help predicting early Staphylococcus aureus ventilator-associated pneumonia?
Les changements quotidiens du microbiote respiratoire peuvent-ils aider à prédire la pneumonie précoce associée à la ventilation assistée à Staphylococcus aureus ?
Résumé
Ventilator-associated pneumonia (VAP) remains the most frequent healthcare-associated
infection in Intensive Care Units (ICUs) with a prevalence of 9–27% [1]. Factors
driving the progression from colonization to infection during VAP development are not
fully elucidated. Metataxonomics [16S rRNA gene next-generation sequencing (NGS)]
has emerged as an efficient tool to investigate pulmonary microbiota. When compared
to conventional aerobic culture, metataxonomics provides additional information which
allows assessing exhaustively the local bacterial community, including anaerobes, that
are fastidious and yet-unculturable organisms. This culture-free approach provides new
insights into respiratory microbiota dynamics and potential mechanisms of VAP development
[2–5]. No study has yet sequentially explored respiratory microbiota dysbiosis
on a daily basis and its potential relationship with the development of early VAP. We
hypothesized post hoc that patients who develop Staphylococcus aureus VAP might
exhibit modified respiratory microbiota during mechanical ventilation (MV) when compared
to patients without VAP. In this pilot study (IRB #464-2021-120), we analyzed the
daily changes of respiratory microbiota in a homogeneous population of patients under
MV without prior exposure to antibiotics or antibiotic treatment during the study period
until potential VAP diagnosis.
Eligible patients were adults admitted to the ICU for an acute brain injury requiring
at least 48 h of MV, with no chronic or acute respiratory disease, and who did not
receive antibiotics in the previous 15 days. If antibiotics were administered during the
study period, patients were secondarily excluded. Endotracheal aspirates (ETA) were
collected every morning from the day of tracheal intubation (day 1) to either the day
of VAP suspicion, the day of extubation or until day 7 whichever occurred first. All
VAP events were blindly adjudicated by two independent ICU physicians