Department of Medicine, South Texas Veterans' Health Care System, San Antonio, TX, USA.
Med Mycol. 2010 Sep;48(6):807-16. doi: 10.3109/13693780903514542.
We examined the utility of agar dilution to screen yeasts for reduced susceptibility to several newer antifungal drugs including echinocandins and azoles. We compared agar dilution susceptibility screening with the Clinical and Laboratory Standards Institute (CLSI) method for Candida isolates. We added echinocandins and azoles to CHROMagar Candida medium prior to its solidification. Assessment of resistance was based on growth characteristics, wherein decreased colony size in the presence of antifungal drugs was used as an indicator of susceptibility. Clinical Candida isolates of C. albicans, C. glabrata, C. parapsilosis, C. tropicalis, C. guilliermondii, C. lusitaniae, C. rugosa and C. dubliniensis were screened for drug susceptibility. Overall, antifungal susceptibility of the yeasts to anidulafungin, caspofungin, micafungin, posaconazole and voriconazole, determined using CHROMagar agar dilution, were shown to be 96, 80, 94, 90 and 97% as accurate, respectively, as those determined by the CLSI method, i.e., within one tube dilution of CLSI MICs. Categorical errors by percentage had a broader range. Major errors noted with anidulafungin, caspofungin and micafungin were 3, 6 and 0%, respectively, while very major errors were 15, 55 and 38%, respectively. Major errors with posaconazole and voriconazole were 12 and 0%, respectively, while very major errors were 0 and 22%, respectively, compared to CLSI standards. Most of the assessment errors were found with C. glabrata and C. parapsilosis. Agar dilution screening for drug susceptibility with the current panel of antifungal drugs is rapid, accurate and effective. However, the determination of resistance or non-susceptibility in yeasts may be more problematic, and may be species dependent.
我们研究了琼脂稀释法在筛选对几种新型抗真菌药物（包括棘白菌素类和唑类药物）敏感性降低的酵母菌中的作用。我们比较了琼脂稀释法与临床和实验室标准化协会（CLSI）方法对念珠菌分离株的药敏筛查。我们在 CHROMagar 念珠菌培养基凝固之前加入棘白菌素类和唑类药物。基于生长特征评估耐药性，即存在抗真菌药物时菌落大小减小作为敏感性的指标。我们筛选了临床分离的白色念珠菌、近平滑念珠菌、光滑念珠菌、热带念珠菌、季也蒙念珠菌、葡萄牙念珠菌、罗鲁阿念珠菌和都柏林念珠菌对药物的敏感性。总的来说，使用 CHROMagar 琼脂稀释法测定酵母菌对安尼卡fungin、卡泊芬净、米卡芬净、泊沙康唑和伏立康唑的药敏结果，与 CLSI 方法相比，准确性分别为 96%、80%、94%、90%和 97%，即在 CLSI MIC 管的一个稀释度内。按百分比计算的分类错误范围较宽。安尼卡fungin、卡泊芬净和米卡芬净的主要错误分别为 3%、6%和 0%，而非常大的错误分别为 15%、55%和 38%，与 CLSI 标准相比。泊沙康唑和伏立康唑的主要错误分别为 12%和 0%，而非常大的错误分别为 0%和 22%。大多数评估错误发生在近平滑念珠菌和光滑念珠菌中。目前使用的抗真菌药物琼脂稀释药敏筛查快速、准确、有效。然而，酵母菌的耐药性或敏感性的判断可能更成问题，并且可能取决于菌种。
