Invasive Candida species infections: a 5 year population-based assessment

Candida species have emerged as important causes of invasive infections and rates of resistance to standard antifungal therapies are rising. The objective of this study was to define the occurrence of, risk factors for, and antifungal susceptibilities of invasive Candida species infections in a large Canadian health region.

Population-based surveillance was conducted for invasive Candida species infections in the Calgary Health Region during a 5 year period and susceptibility testing was performed.

The annual incidence of invasive Candida species infection was 2.9 per 100,000 population (0.2 and 2.8 per 100,000 for central nervous system and bloodstream infection, respectively). The very young and elderly were at highest risk for invasive Candida species infections. Several risk factors for developing invasive Candida species infection were identified with chronic haemodialysis, organ transplant recipient, and cancer patients at highest risk. Thirty percent (56/184; 43 susceptible, dose-dependent and 13 resistant) of isolates demonstrated reduced susceptibility to fluconazole. Only one (1%) isolate had reduced susceptibility to amphotericin B and six (3%) and three (2%) isolates had minimum inhibitory concentrations of >or=1 mg/L to voriconazole and caspofungin, respectively. Overall, 40% of patients died in-hospital for an annual mortality rate of 1.2 per 100,000.

Candida species are an important cause of invasive infection and patients with co-morbidities and extremes of age are at highest risk. Alternatives to fluconazole should be considered for initial empiric therapy in patients with severe invasive Candida species infections.