Prevalence, distribution and antifungal susceptibility profiles of Candida parapsilosis, Candida orthopsilosis and Candida metapsilosis bloodstream isolates

Abstract

The Candida parapsilosis group encompasses three species: C. parapsilosis, Candida orthopsilosis and Candida metapsilosis. These species are phenotypically indistinguishable, and molecular methods are needed for their detection. We analysed 152 unique blood culture isolates of the C. parapsilosis group obtained during 1997-2011. The isolates were screened by PCR amplification of the gene encoding secondary alcohol dehydrogenase, followed by digestion with the restriction enzyme BanI. Isolates with RFLP patterns distinct from those of the C. parapsilosis group were characterized as C. parapsilosis sensu stricto (90.8 %), C. orthopsilosis (8.6 %) and C. metapsilosis (0.6 %). Antifungal susceptibility tests indicated that all isolates were susceptible to itraconazole, amphotericin B and caspofungin. Although C. orthopsilosis and C. metapsilosis isolates were susceptible to fluconazole, higher MICs (≥2 mg l(-1)) were observed for C. orthopsilosis. Three isolates (2.0 %) of C. parapsilosis sensu stricto were resistant to voriconazole. Five C. parapsilosis isolates (3.3 %) were intermediate, and a single isolate (0.7 %) was resistant (MIC 16 mg l(-1)) to fluconazole. These data were confirmed using reference strains. It was observed that C. parapsilosis isolates were less susceptible to all triazoles, and this finding deserves further attention to assess the appearance of cross-resistance phenomena. In conclusion, C. metapsilosis and C. orthopsilosis are involved in a small but significant number of invasive infections in Brazil.