Genetic Diversity and Antifungal Susceptibility of Candida parapsilosis Sensu Stricto Isolated from Bloodstream Infections in Turkish Patients.

Abstract

Candida parapsilosis sensu stricto is an emerging cause of hospital-acquired Candida infections, predominantly in southern Europe, South America, and Asia. We investigated the genetic diversity and antifungal susceptibility profile of 170 independent C. parapsilosis sensu stricto strains obtained from patients with candidemia who were treated at the Ege University Hospital in Izmir, Turkey, between 2006 and 2014. The identity of each strain was confirmed via PCR amplification and digestion of the secondary alcohol dehydrogenase-encoding gene. The 24-h geometric mean minimum inhibitory concentrations of the antifungal agents, in increasing order, were as follows: posaconazole, 0.10µg/mL; voriconazole, 0.21µg/mL; caspofungin, 0.38µg/mL; amphotericin B, 0.61µg/mL; anidulafungin, 0.68µg/mL; and fluconazole, 2.95µg/mL. Microsatellite genotyping of the isolates (using fluorescently labeled primers and a panel of four different short-nucleotide repeat fragments) identified 25, 17, 17, and 8 different allelic genotypes at the CP6, B5, CP4, and CP1 locus, respectively. Posaconazole, caspofungin, and amphotericin B showed the greatest in vitro activity of the tested systemic azole, echinocandin, and polyene agents, respectively, and the observed antifungal susceptibility of the isolates was shown to be independent of their isolation source. We obtained a combined discriminatory power of 0.99 with a total of 130 genotypes for 170 isolates tested. Finally, microsatelliteprofiling analysis confirmed the presence of identical genotype between separate isolates, supporting that effective surveillance and infection-prevention programs are essential to limit the impact of C. parapsilosis sensu stricto on hospitalized patients' health.