Aspergillus fumigatus in blood reveals a "just wait and see" resting stage behavior

Objective: We analyzed changes in A. fumigatus gene expression profile at various stages of an in vitro model of aspergillosis to study the adaptation of A. fumigatus to the blood environment. Results: Most of virulence factors described to be involved in aspergillosis were not activated during the blood phase. We found three active processes to be activated in the later phase that may help to the adaptation: Iron homeostasis, a partial secondary metabolite cluster and the formation of detoxification enzymes. Conclusions: We propose that A. fumigatus is unable to grow in blood and it requires a metabolic change that allows the organism to shut down all uptake and energy-consume mechanisms, resulting in a resting mycelial stage. Overall design: We performed gene expression profile by sequencing mRNA of A. fumigatus that were growm under two conditions, Minimal Medium (M) and human blood (B), and at different times: before placing the fungus in the final medium (pre), at 30' and at 180', with 2 biological replicates per condition.