Effect of fluconazole consumption on long-term trends in candidal ecology

Background: Fluconazole is an antifungal agent that is widely used for the treatment of Candida infection. Because of its favourable safety profile it is extensively used for prophylaxis in patient populations with a substantial risk for Candida infection. At the individual patient level, exposure to fluconazole selects for Candida non-albicans strains such as Candida glabrata and Candida krusei, with reduced susceptibility or intrinsic resistance to fluconazole. The effect of the volume of consumption of fluconazole on candidal ecology, however, is poorly investigated. Objectives: The long-term effect of fluconazole consumption on distribution of species causing candidaemia was investigated in a university hospital during an 11 year period (1994-2004). Methods: In a historical cohort the incidence of nosocomial candidaemia (expressed per 100 000 patient days) was linked with volume consumption of fluconazole [expressed as defined daily doses (DDDs) per 100 000 patient days] and evaluated over time. Results: During the study period 308 episodes of candidaemia occurred (63.3% caused by Candida albicans). The incidence of candidaemia varied from 6.0 to 13.8 per 100 000 patient days. The percentage candidaemia caused by Candida non-albicans spp. varied between 21% and 50%. No trends in the number of candidaemias or in the proportion of C. albicans versus Candida non-albicans spp. were observed. Fluconazole consumption was high but stable ranging from 5013 to 6807 DDDs per 100 000 patient days. No relationship could be demonstrated between volume of fluconazole consumption and Candida spp. distribution (Pearson's correlation coefficient: -0.083; P = 0.808). Conclusions: Despite long-term exposure to fluconazole, no change in candidal ecology was observed