Susceptibilities of Candida species to amphotericin B and fluconazole: The emergence of fluconazole resistance in Candida tropicalis

Abstract

OBJECTIVE: To determine the susceptibilities of Candida species isolated from Taiwan to amphotericin B and fluconazole. DESIGN: Prospective surveillance study. METHODS: Each hospital was asked to submit up to 10 C. albicans and 40 non-albicans Candida species during the collection period, from April 15 to June 15, 1999. One isolate was accepted from each episode of infection. The broth microdilution method was used to determine susceptibilities to amphotericin B and fluconazole. RESULTS: Only 3 of 632 isolates, one each of C. famata, C. krusei, and C. tropicalis, were resistant to amphotericin B. A total of 53 (8.4%) of 632 clinical yeast isolates, consisting of 4% C. albicans, 8% C. glabrata, 15% C. tropicalis, and 70% C. krusei, were resistant to floconnzole. In contrast. no C. Parapsilosis isolate was resistant to fluconazole. Isolates from tertiary-care medical centers had higher rates of resistance to fluconazole than did those from regional and local hospitals (11.4% vs 6.6%). Isolates from different sources showed different levels of susceptibility to fluconazole. All of the isolates with the exception of C. tropicalis and C. krusei isolated from blood were susceptible to fluconazole. A pattern of co-resistance to both amphotericin B and fluconazole was observed. CONCLUSIONS: Non-albicans Candida species had higher rates of resistance to fluconazole than did C. albicans (44 of 395 [11.2%] vs 9 of 237 [3.8%]; P = .002). The increasing rate of fluconazole resistance in C. tropicalis (15%) is important because C. tropicalis is one of the most commonly isolated non-albicans Candida species.