Epidemiology and Molecular Typing of Candida krusei Based on PCRRFLP of the ITS rDNA Regions

Abstract

Purpose: Candida krusei strains are intrinsically resistant for the first choice antifungal. Fast identification of C. krusei as an infectious agent will decrease the risk of choice of not correct therapy. The aim of the present work was to study the epidemiology of Candida krusei infections during 10 years. We also attempt to study the phylogeny of these isolates by PCR- RFLP. Methods: Two hundred five cases of C. krusei candidiasis were referred to laboratory of parasitology mycology, UH Habib Bourguiba of Sfax-Tunisia during 10 years (2006 to 2016). Identification of our strains was performed by conventional methods and by PCR-ITS amplification followed by a digestion with three restriction enzymes MspI, HinfI and HincII. Result: The mean frequency of cases of C. krusei candidiasis was 17.08 per year. Invasive infection represented 10.24%. The superficial infections with C. krusei represented 89.76% of cases. Analysis of the phylogeny tree allowed us to deduce that there is a great diversity in C. krusei strains. No particular genotype has been associated with the sampling site, or department or year of infection. We noted that patient P4 was hosted by three strains with the same genotype. Conclusion: The modification in epidemiology of candidiasis emphasizes the necessity to monitor local incidence, species distribution and susceptibility in order to optimize therapy and outcome. Molecular methods are essential for correct identification of the Candida species in order to obtain clues regarding the source of infection and to apply the correct therapy for the infected individual.