Abstract:

Objective To study the in vitro drug susceptibility of Cryptococcus neoformans isolated clinically from East China in recent years. Methods The minimal inhibitory concentrations （MIC） of Cryptococcus neoformans to fluconazole,flucytosine,amphotericin B,itraconazole and voriconazole were determined by micro-dilution broth method,according to the Clinical and Laboratory Standards Institute （CLSI）M27-A3. The drug-resistant and susceptible-dose dependent （SDD） isolates were further identified by internal transcribed spacer （ITS） sequencing. Results Among 96 isolates,the MIC₉₀（the range of MIC）were 4（0.5-16）μg/mL for fluconazole,4（0.25-64）μg/mL for flucytosine,0.5（0.03-1）μg/mL for amphotericin B,0.5（0.03-1）μg/mL for itraconazole and 0.25（0.03-0.5）μg/mL for voriconazole. All the drug-resistant and SDD isolates were determined as Cryptococcus neoformans var. grubii. Conclusions Cryptococcus neoformans isolated from East China are susceptible to antifungal agents except itraconazole. The main species of insensitive isolates is Cryptococcus neoformans var. grubii.

Key words: Cryptococcus neoformans, Drug susceptibility, Internal transcribed spacer sequencing, var. grubii