Avirulence of Candida albicans CaHK1 mutants in a murine model of hematogenously disseminated candidiasis

Deletion of both alleles of the Candida albicans CaHK1 gene, which causes c ells to flocculate when grown at pH 7.5, a pH comparable to that of mammali an blood, abolishes the ability of the yeast to establish a successful infe ction in a murine model of hematogenously disseminated candidiasis. Within 72 h all mice inoculated with the parental C. albicans strain had died. The mice infected with either the heterozygote or revertant strain, either of which harbors only one functional CaHK1 allele, also succumbed to the infec tion, although survivors were observed for up to 16 days postinfection, How ever, mice inoculated with the Delta cahk1 null strain survived for the cou rse of the infection. These results indicate that CaHK1 is required for the virulence of C. albicans in a murine model of hematogenously disseminated candidiasis. In contrast, CaHK1 is not required for the virulence of C. alb icans in a rat model of vaginal candidiasis.