Molecular epidemiology of late recurrent candidaemia—a population-based study in Iceland

Abstract

Candidaemia is associated with high patient mortality. Among those who survive an initial episode of candidaemia, the incidence of recurrent episodes has been incompletely defined. All patients in Iceland with candidaemia in 1980–2008 were identified, and clinical information was reviewed. Episodes of candidaemia in the same patient were considered to be separate if they occurred ≥1 month apart or were caused by different Candida species. The isolates were genotyped by using PCR fingerprinting, and antifungal susceptibility was determined. During the 29-year period, candidaemia was diagnosed in 307 patients in Iceland, 298 of whom (97.1%) had a single episode. Overall, 206 patients survived >1 month from the first episode and were therefore at risk of recurrence, yielding 1062 patient-years of observation in the survivors. Of those, nine (4.4%) later developed recurrent candidaemia. The median time between recurrences was 6 months (range, <1 month to 14 years). Patients with late recurrences were younger (p 0.012) and more likely to have underlying gastrointestinal diseases than patients with single episodes (55.6% vs. 18.5%, respectively; p 0.017). The recurrences were caused by identical Candida sp. genotypes in two of 13 cases (15%), but by different species or dissimilar genotypes in eight of 13 (62%); isolates were missing in three cases. In conclusion, late recurrent candidaemia was a relatively rare event, and younger patients with gastrointestinal disorders were more prone to recurrent infections. The majority of late recurrences represented re-infections with new Candida strains that were susceptible to common antifungal agents.