An Integrated Analysis Approach to Unravel the Aspergillus Community in the Hospital Environment.

The genus Aspergillus, widely distributed across natural and urban environments, may cause allergies and opportunistic infections such as chronic or invasive pulmonary aspergillosis. Its high pathogenic potential for immunocompromised patients, together with the alarming increase of azole resistance reported in clinical and environmental isolates, claims urgent actions to assess and control the Aspergillus community in hospital environments. To contribute to that, here, we combine a large environmental survey covering numerous air and surface samples from different zones of three hospitals in Spain, with an integrated approach including general and selective culture- and eDNA-based analyses. Despite the high prevalence of Aspergillus observed, present in almost all indoor zones (mostly in air but also on surfaces) of the three hospitals, its relative abundance in the whole fungal community was limited and dependent on the used methods, with median values ranging from 1.4% (eDNA data) and 6.8% (cultivation at 28 °C) to 28.3% (cultivation at 37 °C). Remarkably, the most protected zones (intensive care units) showed the highest proportion of Aspergillus eDNA sequences. A total of 32 species belonging to 10 Aspergillus sections were molecularly identified, including well-known causal agents of invasive pulmonary infections such as A. fumigatus, A. flavus, A. terreus, A. niger, A. oryzae, A. sydowii, and A. tubingensis. This highlights the importance of such environmental assessments for monitoring and controlling the fungal burden in hospitals.