Competitive fitness of fluconazole-susceptible isolates F2, B3, 5833, and TW1 (light gray bars) and matched fluconazole-resistant isolates F5, B4, 6692, and TW17 (dark gray bars), respectively, in a mouse model of disseminated candidiasis. In each case, the susceptible isolate was mixed with two independently generated RFP-labeled derivatives of the matched resistant isolate and the resistant isolate was mixed with two independently generated RFP-labeled derivatives of the matched susceptible isolate. For all comparisons, each of the four mixtures was used to infect 3 mice (5 mice were infected with the B3/B4ADH1R1B pair); i.e., the competitive fitness of each isolate pair was tested in 12 mice (14 mice for B3/B4). Shown are the relative proportions of the strains in the inoculum (day 0) and in the kidneys after 6 days of infection. Results are the means and standard deviations of the 12 (or 14) coinfection experiments. Significant differences in the proportions of the resistant isolates in the kidneys compared to the inoculum are indicated by asterisks (P < 0.05). See Data Set S5 for details.