High bacterial and fungal burden detected in bronchoalveolar lavage (BAL) samples of COVID-19 patients with acute respiratory distress (ARDS) has been linked to higher deaths.

The study, out of Amsterdam, was designed to assess the relationship between lung microbiota and clinical outcomes of COVID-19-related ARDS.

Published in the American Journal of Respiratory and Critical Care Medicine, the study included 114 mechanically ventilated patients with COVID-19 and ARDS who underwent bronchoscopy with BAL.

Researchers found that those patients with the highest bacterial and fungal burdens were less likely to be extubated and to survive than those with lower levels. More than half of the patients in the study died.

“Our findings confirm the importance of the lung microbiome in ARDS and COVID-19 and highlight the significance of the — often overlooked — pulmonary fungal burden in critically ill patients,” Dr. Robert F.J. Kullberg and others wrote.

The study’s endpoint was defined as successful extubation within 60 days after intubation.

The authors say this study validates earlier research which showed increased bacterial burden to be associated with higher mortality but is the first to link a higher fungal burden with high fatality in COVID patients with ARDS.

“In the context of other investigations on lower airway samples from critically ill patients with COVID-19, these results solidify the notion that it is not just uncontrollable SARS-CoV-2 infection that kills patients with COVID-19, though that’s likely one big part of it,” wrote authors of a related editorial.

More research is needed, they added.

“Disentangling this web of microbial, pathogen and host dynamics is the only way we will be able to risk-stratify patients and identify treatable traits,” the authors of the editorial wrote.