Species distribution and in vitro susceptibility to three antifungal triazoles of clinical Candida isolates from a five-year nation-wide survey in Japan

We collected 1,486 clinical isolates of Candida species over a five-year period (2001 to 2005) in Japan and examined their species distribution and patterns of susceptibility to three antifungal azoles (fluconazole, itraconazole, and voriconazole). The most frequently isolated species was C. albicans, being followed by C. glabrata, C. tropicalis, C. parapsilosis and C. krusei, in this order, at every survey. Isolation rates of C. albicans were 58.6%, 57.3% and 61.6% in the 2001∙2002, 2003 and 2005 surveys, respectively. Azole resistance was scarcely or not detected among isolates of C. albicans and C. parapsilosis. Overall resistance rates to fluconazole, itraconazole and voriconazole were: 4.6, 4.6 and 0.9%, respectively, among C. glabrata isolates; 2.3, 2.3 and 0.8%, respectively, among C. tropicalis isolates; and 59, 6.9 and 6.9%, respectively, among C. krusei isolates. An increase in azole resistance over time was only seen with fluconazole resistance of C. krusei. Voriconazole-resistant Candida species isolates exhibited complete cross-resistance to fluconazole and itraconazole.