Lung microbiota of ARDS patients due to COVID-19 receiving ECMO

Background Diversity of the microbiota, which is essential for lower airway homeostasis, is greatly altered in acute respiratory distress syndrome (ARDS). Extracorporeal membrane oxygenation (ECMO) is the ultimate protective treatment for the lungs of patients with severe ARDS, but little is known about its effect on the lung microbiota of these patients. The aim of this study was to evaluate the effect of ECMO on the lung microbiota of ARDS patients. Methods This was a prospective, observational clinical study of ARDS patients with COVID-19. We performed 16S rRNA and fungal ITS1 profiling and shotgun sequencing on bronchoalveolar lavage fluid (BALF) samples collected from patients with ARDS due to COVID-19. Results BALF was collected from 13 patients, five of whom underwent ECMO. The median age of the patients with ECMO was significantly younger than that of those without ECMO (44 [IQR: 36–48] years vs. 64 [IQR: 53–74] years, p < 0.007). The median APACHE II score was significantly higher in the patients with ECMO versus those without ECMO (20 [IQR: 17–22] vs. 15 [IQR: 12–18], p = 0.018). In all ARDS patients, Pseudomonas was the most abundant of the bacteria. The patients with ECMO had more Pseudomonas and more Klebsiella than those without ECMO. The most abundant fungi were unspecified fungi in the patients with ECMO and Emmia lacerata in the patients without ECMO. Alpha diversity of bacteria and fungi did not differ significantly between the two groups. Human betaherpesvirus 5 and human alphaherpesvirus 1 were predominant in all patients, with human betaherpesvirus 5 decreasing over time in the ECMO patients. Conclusion The patients with ARDS due to COVID-19 who received ECMO had a different lung microbiota than those who did not receive ECMO.