Mycobiome analyses of critically ill COVID-19 patients suggests antifungal prophylaxis may be protective against A. fumigatus-associated mortality

Rationale: Covid-associated pulmonary aspergillosis (CAPA) is a life-threatening complication in patients with severe COVID -19. Previously, acute respiratory distress syndrome in patients with COVID-19 has been associated with lung fungal dysbiosis, evidenced by reduced microbial diversity and Candida colonisation. Increased fungal burden in the lungs of critically ill COVID-19 patients is linked to prolonged mechanical ventilation and increased mortality. However, specific mycobiome signatures associated with severe COVID-19 in the context of survival and antifungal drug prophylaxis have not yet been determined and such knowledge could have an important impact on treatment. Objectives: To understand the composition of the respiratory mycobiome in critically ill COVID -19 patients with and without CAPA, the impact of antifungal use and its role in patient outcome. Methods: We performed a multi-national study of 39 COVID-19 patients in intensive care units (ICU) with and without CAPA. Respiratory mycobiome was profiled using ITS1 sequencing and Aspergillus fumigatus burden was further validated using qPCR. Fungal communities were investigated using alpha diversity, beta diversity, taxa prevalence and taxa abundances. Measurements and Main Results: Respiratory mycobiomes were dominated by Candida and Aspergillus. There was no significant association with corticosteroid use or CAPA diagnosis and respiratory fungal communities. Increased A. fumigatus burden was associated with mortality. The use of antifungals at ICU admission was associated with an absence of A. fumigatus. Conclusions: Our findings suggest that systemic antifungal treatment at ICU admission may be protective against A. fumigatus-associated mortality in CAPA.