Dynamic virulence: real-time assessment of intracellular pathogenesis links Cryptococcus neoformans phenotype with clinical outcome.

While a myriad of studies have examined host factors that predispose persons to infection with the opportunistic fungal pathogen Cryptococcus neoformans, comparatively little has been done to examine how virulence factor differences among cryptococcal isolates may impact outcome. In the recent report by Alanio et al. (A. Alanio, M. Desnos-Ollivier, and F. Dromer, mBio 2:e00158-11, 2011), novel flow cytometry-based techniques were employed to demonstrate an association between the phenotype of C. neoformans-macrophage interactions, as measured by phagocytosis and intracellular replication, and patient outcomes, as determined by positive cultures on therapy and survival. These experiments establish that the prognosis of patients with cryptococcosis is influenced by the phenotypic properties of the infecting fungal isolate.