In vitro antifungal susceptibility of 80 Cryptococcus neoformans isolates / 中华传染病杂志

ABSTRACT

Objective To determine in vitro drug susceptibility to five antifungal agents of clinical Cryptococcus neoformans strains isolated from different areas of China in recent ten years. Methods Eighty clinical isolates of Cryptococcus neoformans were isolated from Shanghai, Guangdong, Fujian, Beijing and some other areas of China from 1998 to 2007. The minimal inhibitory concentrations (MIC) of the isolates to five antifungal agents, including amphotericin B, fluconazole, flucytosine, itraconazole and voriconazole, were determined using broth microdilution procedure (document M27-A2) recommended by the Clinical and Laboratory Standards Institute (CLSI). Kruskal-Wallis rank sum test was employed for the statistical analysis. Results The MIC50 of the Cryptococcus neoforrnans isolates tested for amphotericin B, fluconazole, flucytosine, itraconazole and voriconazole were 0.5, 4, 2, 0.25 and ≤0.031 3 mg/L, respectively; and the MIC<,90> of the isolates tested for the above antifungal agents were 1, 8, 4, 0.5 and 0.062 5 mg/L, respectively. Among the tested isolates, 3 (3.8 %) were resistant to flucytosine, 4 (5.0 %) were resistant to itraconazole. All isolates were susceptible to amphotericin B and voriconazole. There was no significant difference in MIC of the strains isolated from any particular years to the five agents (χ2=0.500,2.687,2.211, 2.660,0.677,P>0.05). Conclusions The Cryptococcusneoformans isolates are highly susceptible to the five antifungal agents, while a few strains are resistant to flucytosine or itraconazole. The drug susceptibilities of the strains isolated from particular years are similar.