Surface display of Gaussia princeps luciferase allows sensitive fungal pathogen detection during cutaneous aspergillosis.

ABSTRACT

Non-invasive imaging techniques in microbial disease models have delivered valuable insights in the intimate pathogen-host interplay during infection. Here we describe evaluation and validation of a transgenic bioluminescence reporter strain of the human-pathogenic mold Aspergillus fumigatus, one of the main fungal pathogens affecting immunocompromised individuals. Expression and surface display of the Gaussia princeps luciferase allowed sensitive and rapid detection of luminescence emitted from this strain after substrate addition, with photon fluxes strongly correlating to the amounts of fungal conidia or germlings. The reporter strain allowed spatio-temporal monitoring of infection in a cutaneous model of aspergillosis, where neutropenic mice maintained the fungal burden while immunocompetent ones were able to clear it entirely. Most importantly, antifungal therapy could be followed in this type of disease model making use of the bioluminescent A. fumigatus strain. In conclusion, combining sensitivity of the Gaussia luciferase with a surface display expression system in the fungal host allows longitudinal infection studies on cutaneous forms of aspergillosis, providing perspective on drug screening approaches at high-throughput.