Fig. 1

Chronology of Aspergillus infections among COVID-19 patients in the ICU and environmental mycological results. After lowering to a negative pressure in the 15 ICU rooms, probable or proven pulmonary aspergillosis developed in six patients and Aspergillus colonization in two patients. Analysis of the air in the three of four rooms tested, before any corrective measures, were positive for Aspergillus fumigatus. Despite decreasing the negative air pressure to − 5 Pa, high levels of Asp. fumigatus remained positive in the room air. When the air pressure in the rooms was brought to around 0 Pa, the number of Aspergillus colonies markedly diminished and then became undetectable. Since then, no patient developed Asp. fumigatus infection. AF, Asp. fumigatus; AF (+), presence of Asp. fumigatus; AF (−), absence of Asp. fumigatus