Epidemiology and Antifungal Susceptibility of BloodstreamCandidaIsolates in Quebec: Report on 453 Cases between 2003 and 2005

Abstract

BACKGROUND: Between May 2003 and April 2005, a population-based surveillance ofCandidabloodstream infections was conducted in Quebec. A total of 453 episodes of candidemia (464 yeast isolates) from 54 participating hospitals were studied.RESULTS: The annual incidence rate was three per 100,000 population. Global hospital mortality was 38%. The most common predisposing factors were the presence of an intravascular catheter (80%), use of antibacterial therapy (67%), stay in an intensive care unit (49%), use of parenteral nutrition (32%) and intra-abdominal surgery (31%). Fluconazole alone or in association with other antifungals was used for treatment in over 80% of cases.Candida albicanscomprised 62% of isolates, followed byCandida glabrata(17%),Candida parapsilosis(9%),Candida tropicalis(5%),Candida lusitaniae(3%) andCandida krusei(3%). Of the 288C albicansisolates, seven (2%) were resistant to flucytosine, one to fluconazole and none to itraconazole or voriconazole. Of the 75 non-C albicansspecies isolates with reduced susceptibility to fluconazole (minimum inhibitory concentration [MIC] 16 μg/mL or greater), none were susceptible to itraconazole (MIC 0.12 mg/L or lower), whereas 71 (95%) were susceptible to voriconazole (MIC 1 μg/mL or lower). However, only five of 12 (42%) fluconazole-resistant isolates were susceptible to voriconazole. Posaconazole, ravuconazole and caspofungin displayed a broad spectrum of activity against these isolates, with MICs of 1 mg/L or lower in 56%, 92% and 100% of isolates, respectively. Overall, a correlation (r2>0.87) was observed among increasing fluconazole MICs and the geometric mean MICs of itraconazole, voriconazole, posaconazole and ravuconazole.CONCLUSIONS: These surveillance results when compared with those of the 1993 to 1995 survey confirm little variation in the distribution of species causing invasiveCandidainfection over a 10-year period in Quebec, as well as the continuous excellent overall in vitro activity of fluconazole.