Prospective multicenter study of the epidemiology, molecular identification, and antifungal susceptibility of Candida parapsilosis, Candida orthopsilosis, and Candida metapsilosis isolated from patients with candidemia.

A 13-month prospective multicenter study including 44 hospitals was carried out to evaluate the epidemiology of Candida parapsilosis complex candidemia in Spain. Susceptibility to amphotericin B, flucytosine, fluconazole, itraconazole, voriconazole, posaconazole, anidulafungin, caspofungin, and micafungin was tested by the microdilution colorimetric method. A total of 364 C. parapsilosis complex isolates were identified by molecular methods: C. parapsilosis (90.7%), Candida orthopsilosis (8.2%), and Candida metapsilosis (1.1%). Most candidemias (C. parapsilosis, 76.4%; C. orthopsilosis, 70.0%; C. metapsilosis, 100%) were observed in adults. No C. orthopsilosis or C. metapsilosis candidemias occurred in neonates. C. parapsilosis was most frequent in adult intensive care unit (28.8%), surgery (20.9%), and internal medicine (19.7%) departments; and C. orthopsilosis was most frequent in hematology (28.6%), pediatrics (12.0%), and neonatology (11.5%) departments. The geographic distribution of C. orthopsilosis and C. metapsilosis was not uniform. According to CLSI clinical breakpoints, all C. orthopsilosis and C. metapsilosis isolates were susceptible to the nine agents tested. Resistance (MICs > 1 mg/liter) was observed only in C. parapsilosis: amphotericin B, posaconazole, itraconazole, and caspofungin (0.3% each), anidulafungin (1.9%), and micafungin (2.5%). Applying the new species-specific fluconazole and echinocandin breakpoints, the rates of resistance to fluconazole for C. parapsilosis and C. orthopsilosis increased to 4.8% and 0.3%, respectively; conversely, for C. parapsilosis they shifted from 1.9 to 0.6% (anidulafungin) and from 2.5 to 0.6% (micafungin). Our study confirms the different prevalence of C. parapsilosis complex candidemia among age groups: neither C. orthopsilosis nor C. metapsilosis was isolated from neonates; interestingly, C. metapsilosis was isolated only from adults and the elderly. The disparity in antifungal susceptibility among species could be important for therapy.

Prevalence and antifungal susceptibility patterns of new cryptic species inside the species complexes Candida parapsilosis and Candida glabrata among blood isolates from a Spanish tertiary hospital.

OBJECTIVES: There is scarce information on the clinical relevance and antifungal susceptibility of Candida bracarensis, Candida nivariensis, Candida orthopsilosis and Candida metapsilosis. The objective of this study was to assess the prevalence and in vitro antifungal susceptibility of these cryptic species among 173 blood isolates previously identified as Candida glabrata or Candida parapsilosis at the Hospital of Cruces (Barakaldo, Spain). The survey was extended to 518 clinical isolates from the culture collection of the Universidad del País Vasco-Euskal Herriko Unibertsitatea (UPV-EHU; Bilbao, Spain). METHODS: In vitro susceptibilities to 5-fluorocytosine, amphotericin B, anidulafungin, caspofungin, fluconazole, itraconazole, micafungin, posaconazole and voriconazole were tested. RESULTS: All isolates of C. glabrata were identified as C. glabrata sensu stricto. Inside the C. parapsilosis complex, 2.4% of isolates from the Hospital of Cruces and 5.8% from the UPV-EHU were C. metapsilosis or C. orthopsilosis. Of 457 isolates, 435 (95.19%) were C. parapsilosis sensu stricto, 11 (2.41%) C. metapsilosis and 11 (2.41%) C. orthopsilosis. Only seven blood isolates were C. metapsilosis (0.44%) or C. orthopsilosis (1.09%). These cryptic species were also isolated from other relevant clinical specimens. Four C. parapsilosis sensu stricto (5.6%) were susceptible dose-dependent, and one was resistant to both fluconazole and voriconazole (1.4%). Moreover, 19 isolates of C. parapsilosis sensu stricto (26.4%) were intermediately susceptible to itraconazole and higher concentrations of echinocandins were needed to inhibit this species. Most C. orthopsilosis and C. metapsilosis were susceptible to all antifungal agents tested, but one otic isolate of C. metapsilosis was resistant to fluconazole and 5-fluorocytosine. CONCLUSIONS: C. metapsilosis and C. orthopsilosis are associated with human disease and show a different antifungal susceptibility profile compared with C. parapsilosis sensu stricto.