Pfaller M A, Barry A L
Department of Pathology, University of Iowa College of Medicine, Iowa City, USA.
Mycopathologia. 1995;130(1):3-9. doi: 10.1007/BF01104343.
A comparative evaluation of the in vitro susceptibilities of 597 clinical yeast isolates to amphotericin B, fluconazole, and 5-fluorocytosine (5FC) was conducted. The broth macrodilution reference method of the National Committee for Clinical Laboratory Standards (NCCLS, M27-P) was adapted to the microdilution method. Microdilution endpoints for amphotericin B were scored as the lowest concentration in which a score of 0 (complete absence of growth) was observed and for 5FC and fluconazole as the lowest concentration in which a score of 2 (prominent decrease in turbidity; MIC-2) was observed compared to the growth control. The MIC values were read after 24 and 48 h incubation. A broad range of MIC values was observed with each antifungal agent. Amphotericin B was very active (MIC90 < or = 1.0 microgram/ml) against all of the yeast isolates with the exception of C. lusitaniae (MIC90 > or = 2.0 micrograms/ml). Fluconazole was most active against C. parapsilosis (MIC90 of 1.0 microgram/ml) and least active against C. krusei (MIC90 of 32 micrograms/ml). 5FC was most active against C. albicans, C. parapsilosis, C. tropicalis, and T. glabrata (MIC90 < or = 1.0 microgram/ml) and was least active against C. krusei and C. lusitaniae (MIC90 > or = 16 micrograms/ml). These data indicate that the microdilution method, performed in accordance with M27-P, provides a means of testing larger numbers of yeast isolates against an array of antifungal agents and allows this to be accomplished in a reproducible and standardized manner. Given these results, it appears that the microdilution method may be a useful alternative to the macrodilution reference method for susceptibility testing of yeasts.
对597株临床酵母分离株进行了两性霉素B、氟康唑和5-氟胞嘧啶（5FC）的体外药敏比较评估。美国国家临床实验室标准委员会（NCCLS，M27-P）的肉汤大稀释参考方法被改编为微量稀释法。两性霉素B的微量稀释终点被记录为观察到生长评分为0（完全无生长）的最低浓度，5FC和氟康唑的微量稀释终点为观察到与生长对照相比生长评分为2（浊度显著降低；MIC-2）的最低浓度。在孵育24小时和48小时后读取MIC值。每种抗真菌药物都观察到了广泛的MIC值范围。两性霉素B对除葡萄牙念珠菌（MIC90≥2.0微克/毫升）外的所有酵母分离株都非常有效（MIC90≤1.0微克/毫升）。氟康唑对近平滑念珠菌最有效（MIC90为1.0微克/毫升），对克柔念珠菌最无效（MIC90为32微克/毫升）。5FC对白色念珠菌、近平滑念珠菌、热带念珠菌和光滑念珠菌最有效（MIC90≤1.0微克/毫升），对克柔念珠菌和葡萄牙念珠菌最无效（MIC90≥16微克/毫升）。这些数据表明，按照M27-P进行的微量稀释法提供了一种针对一系列抗真菌药物检测大量酵母分离株的方法，并能以可重复和标准化的方式完成。鉴于这些结果，微量稀释法似乎可能是酵母药敏试验中肉汤大稀释参考方法的一种有用替代方法。
