Susceptibilities ofCandidaSpecies to Amphotericin B and Fluconazole: The Emergence of Fluconazole Resistance inCandida tropicalis

Abstract

AbstractObjective:To determine the susceptibilities ofCandidaspecies isolated from Taiwan to amphotericin B and fluconazole.Design:Prospective surveillance study.Methods:Each hospital was asked to submit up to 10C. albicansand 40non-albicans Candidaspecies 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 ofC. famata, C. krusei,andC. 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 fluconazole. In contrast, noC. parapsilosisisolate 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 ofC. tropicalisandC. kruseiisolated from blood were susceptible to fluconazole. A pattern of co-resistance to both amphotericin B and fluconazole was observed.Conclusions:Non-albicans Candidaspecies had higher rates of resistance to fluconazole than didC. albicans(44 of 395 [11.2%] vs 9 of 237 [3.8%];P= .002). The increasing rate of fluconazole resistance inC. tropicalis(15%) is important becauseC. tropicalisis one of the most commonly isolatednon-albicans Candidaspecies.