Species distribution and antifungal susceptibility patterns of Candida species: Is low susceptibility to itraconazole a trend in Malaysia?

Resistance to antifungal agents has increased in Candida spp., especially in non-albicans species. Recent findings reported a strikingly low susceptibility in Candida spp. towards itraconazole in Malaysia. In this study, a colorimetric broth dilution method was utilized to determine the susceptibility of Candida spp. isolated in Kuala Lumpur Hospital within a six month period. A total of 82 isolates from blood, peritoneal and other fluids were tested against 8 antifungal agents using the Sensititre Yeast One method. These comprised of 32 (39%) C. albicans, 17 (20.7%) C. glabrata, 15 (18.3%) C. tropicalis, 13 (15.9%) C. parapsilosis, two (2.4%) C. sake and 1 (1.2%) each of C. pelliculosa, C. rugosa and Pichia etchellsii/carsonii. Overall, susceptibility of all isolates to caspofungin was 98.8%, amphotericin B, 97.6%; 5-flucytosine, 97.6%; voriconazole, 97.6%; posaconazole, 87.8%; fluconazole, 82.9%; ketoconazole, 79.3%; and itraconazole, 56.1%. A total of 18 Candida spp. isolates (22 %) were resistant to at least one antifungal agent tested, and half of these were resistant to three or more antifungal agents. C. glabrata was the most frequently identified resistant species (10 isolates), followed by C. tropicalis (4 isolates), C. parapsilosis (3 isolates) and C. albicans (1 isolate). Resistance was highest against ketoconazole (20.9%), followed by itraconazole (13.4%). However, 30.5% of isolates were susceptible-dose dependent towards itraconazole. Long-term usage of itraconazole in Malaysia and a predominance of nonalbicans species may account for the results observed in this study. In conclusion, susceptibility to antifungal drugs is species-dependent among Candida spp.; reduced susceptibility to itraconazole is concomitant with the high number of non-albicans Candida species isolated in Malaysia.