University of Iowa College of Medicine, Iowa City, IA, USA.
Diagn Microbiol Infect Dis. 2012 Aug;73(4):365-8. doi: 10.1016/j.diagmicrobio.2012.05.008. Epub 2012 Jun 20.
A commercially prepared dried colorimetric microdilution panel (Sensititre Yeast One, TREK Diagnostic Systems, Cleveland, OH, USA) was compared in 3 different laboratories with the Clinical and Laboratory Standards Institute (CLSI) reference microdilution method by testing 2 quality control strains, 25 reproducibility strains, and 404 isolates of Candida spp. against anidulafungin, caspofungin, and micafungin. Reference CLSI BMD MIC end points and YeastOne colorimetric end points were read after 24 h of incubation. Excellent (100%) essential agreement (within 2 dilutions) between the reference and colorimetric MICs was observed. Categorical agreement (CA) between the 2 methods was assessed using the new species-specific clinical breakpoints (CBPs): susceptible (S), ≤0.25 μg/mL; intermediate (I), 0.5 μg/mL; and resistant (R), ≥1 μg/mL, for C. albicans, C. tropicalis, and C. krusei, and ≤2 μg/mL (S), 4 μg/mL (I), and ≥8 μg/mL (R) for C. parapsilosis and all 3 echinocandins. The new CBPs for anidulafungin and caspofungin and C. glabrata are ≤0.12 μg/mL (S), 0.25 μg/mL (I), and ≥0.5 μg/mL (R), whereas those for micafungin are ≤0.06 μg/mL (S), 0.12 μg/mL (I), and ≥0.25 μg/mL (R). Due to the lack of CBPs for any of the echinocandins and C. lusitaniae, the epidemiological cutoff values (ECVs) were used for this species to categorize the isolates as wild-type (WT; MIC ≤ECV) and non-WT (MIC >ECV), respectively, for anidulafungin (≤2 μg/mL/>2 μg/mL), caspofungin (≤1 μg/mL/>1 μg/mL), and micafungin (≤0.5 μg/mL/>0.5 μg/mL). CA ranged from 93.6% (caspofungin) to 99.6% (micafungin) with less than 1% very major or major errors. The YeastOne colorimetric method remains comparable to the CLSI BMD reference method for testing the susceptibility of Candida spp. to the echinocandins when using the new (lower) CBPs and ECVs. Further study using defined fks mutant strains of Candida is warranted.
一种市售的干燥比色微量稀释板（Sensititre Yeast One，TREK 诊断系统，克利夫兰，俄亥俄州，美国）在 3 个不同的实验室中与临床和实验室标准协会（CLSI）参考微量稀释法进行了比较，使用 2 种质控菌株、25 种重现性菌株和 404 株念珠菌属对安尼度凡、卡泊芬净和米卡芬净进行了检测。在孵育 24 小时后，参考 CLSI BMD MIC 终点和 YeastOne 比色终点被读取。参考和比色 MIC 之间观察到极好的（100%）基本一致性（在 2 个稀释度内）。使用新的特定种属的临床折点（CBPs）评估 2 种方法的分类一致性（CA）：敏感（S），≤0.25μg/mL；中间（I），0.5μg/mL；和耐药（R），≥1μg/mL，适用于白念珠菌、热带念珠菌和克柔念珠菌，以及≤2μg/mL（S）、4μg/mL（I）和≥8μg/mL（R），适用于近平滑念珠菌和所有 3 种棘白菌素。安尼度凡和卡泊芬净以及光滑念珠菌的新 CBPs 为≤0.12μg/mL（S）、0.25μg/mL（I）和≥0.5μg/mL（R），而米卡芬净的新 CBPs 为≤0.06μg/mL（S）、0.12μg/mL（I）和≥0.25μg/mL（R）。由于缺乏任何棘白菌素和葡萄牙念珠菌的 CBPs，因此使用流行病学截断值（ECVs）对该种属进行分类，将分离株分别归类为野生型（WT；MIC≤ECV）和非 WT（MIC＞ECV），分别适用于安尼度凡（≤2μg/mL/＞2μg/mL）、卡泊芬净（≤1μg/mL/＞1μg/mL）和米卡芬净（≤0.5μg/mL/＞0.5μg/mL）。CA 范围从 93.6%（卡泊芬净）到 99.6%（米卡芬净），错误率低于 1%。当使用新的（更低）CBPs 和 ECVs 时，YeastOne 比色法仍然与 CLSI BMD 参考方法相当，可用于测试念珠菌属对棘白菌素的敏感性。需要进一步使用明确的 fks 突变株的研究来验证。
