BACKGROUND:With the following report we want to present an unusual case of a patient suffering from acute respiratory distress syndrome with early discovery of bacterial pathogens in bronchoalveolar liquid samples that developed a fatal undiscovered disseminated fungal infection. CASE PRESENTATION:A 67-year-old man was admitted to our university hospital with dyspnea. Progressive respiratory failure developed leading to admission to the intensive care unit, intubation and prone positioning was necessary. To ensure adequate oxygenation and lung protective ventilation veno-venous extracorporeal membrane oxygenation was established. Despite maximal therapy and adequate antiinfective therapy of all discovered pathogens the condition of the patient declined further and he deceased. Postmortem autopsy revealed Mucor and Aspergillus mycelium in multiple organs such as lung, heart and pancreas as the underlying cause of his deterioration and death. CONCLUSION:Routine screening re-evaluation of every infection is essential for adequate initiation and discontinuation of every antiinfective therapy. In cases with unexplained deterioration and unsuccessful sampling the possibility for diagnostic biopsies should be considered.