Geographic distribution and antifungal susceptibility of the newly described species Candida orthopsilosis and Candida metapsilosis in comparison to the closely related species Candida parapsilosis.

Candida orthopsilosis and Candida metapsilosis are recently described species, having previously been grouped with the more prevalent species Candida parapsilosis. Current literature contains very little data pertaining to the distributions and antifungal susceptibilities of these Candida species. We determined the species and antifungal susceptibilities of 1,929 invasive clinical isolates from the ARTEMIS antifungal surveillance program collected between 2001 and 2006 and identified as C. parapsilosis using Vitek and conventional methods. Of the 1,929 isolates of presumed C. parapsilosis tested, 117 (6.1%) were identified as C. orthopsilosis and 34 (1.8%) as C. metapsilosis. The percentage of presumed C. parapsilosis isolates found to be C. orthopsilosis varied greatly by region, with the highest percentage (10.9%) from South America and the lowest (0.7%) from Africa. The MIC distributions of the C. orthopsilosis and C. metapsilosis isolates were statistically significantly lower than those of C. parapsilosis for all drugs except fluconazole, for which they were significantly higher (P < 0.001 for all). No C. orthopsilosis or C. metapsilosis isolates were fluconazole resistant, and all were susceptible to caspofungin, anidulafungin, and micafungin.