Fatal Disseminated Cryptococcus gattii Infection in New Mexico
Figure 4
Strain R4569 is hypovirulent compared to VGII strains R265 and R272.
a. Eight mice per group were intranasally inoculated with 1×105 CFU of each strain and monitored for disease. Mice infected with C. neoformans strain H99 or C. gattii strain R265 had mean survival times of 23.5 and 27 days, respectively. 87.5% of mice survived infection with R272, and all mice infected with R4569 survived. Survival curves between R272 and R4569 were not significantly different, but fungal burden determination at day 50 post-infection revealed significantly less yeast in the lungs and brains of mice infected with R4569 (p<0.05, Student's t-test). b. Sections of lung from mice infected with R272 show greater numbers of organisms as compared to infections from R4569. There are also increased numbers of lymphocytes and macrophages around aggregates of yeast with R272 than observed with R4569. Additionally, yeasts are found within “foamy” macrophages with R4569 (arrows) suggesting greater control of the infection.