FIG 6.
Heteroresistant clones were more virulent in C57/BL6 mice than in the original strains. Six mice per group were inoculated by the intratracheal (A) and intravenous (B) routes with 106 cells of the original cells or heteroresistant clones of strains L135/03 and L27/01. Animals were monitored daily. The test was repeated twice. C57BL/6 mice were inoculated by the intratracheal route with 106 cells of the original cell lines or heteroresistant clones of strain L135/03. Lungs (C) and brain (D) were removed, homogenized, diluted, and plated onto Sabouraud dextrose agar for measurement of CFU after 10 days postinfection. (E) Level of heteroresistance to itraconazole of C. gattii recovered from mice. (F) Histopathological analysis of lungs 10 days postinoculation with original L135/03 strains showed few yeasts (arrow) and intense, coalescent to diffuse inflammation. (G) Lungs of mice infected with the L135/03 heteroresistant clone showed numerous yeasts (arrow) and mild inflammation. HE was used as the stain, and the magnification is ×200. (H) Score of C. gattii amount and inflammatory lesions intensity in the lungs of C57BL/6 mice. Statistical differences between the original cells and their heteroresistant clones are represented by the horizontal line and asterisks (P < 0.05). O, original; H, heteroresistant; ND, nondetected.