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.

Polyurethane (PUR) plastics is widely used because of its unique physical and chemical properties. However, unreasonable disposal of the vast amount of used PUR plastics has caused serious environmental pollution. The efficient degradation and utilization of used PUR plastics by means of microorganisms has become one of the current research hotspots, and efficient PUR degrading microbes are the key to the biological treatment of PUR plastics. In this study, an Impranil DLN-degrading bacteria G-11 was isolated from used PUR plastic samples collected from landfill, and its PUR-degrading characteristics were studied. Strain G-11 was identified as Amycolatopsis sp. through 16S rRNA gene sequence alignment. PUR degradation experiment showed that the weight loss rate of the commercial PUR plastics upon treatment of strain G-11 was 4.67%. Scanning electron microscope (SEM) showed that the surface structure of G-11-treated PUR plastics was destroyed with an eroded morphology. Contact angle and thermogravimetry analysis (TGA) showed that the hydrophilicity of PUR plastics increased along with decreased thermal stability upon treatment by strain G-11, which were consistent with the weight loss and morphological observation. These results indicated that strain G-11 isolated from landfill has potential application in biodegradation of waste PUR plastics.
Plastics/metabolism* ; Polyurethanes/chemistry* ; RNA, Ribosomal, 16S ; Bacteria/genetics* ; Biodegradation, Environmental