Mycology Laboratory, New York State Department of Health, Wadsworth Center, Albany, NY, USA.
Westchester Medical Center/New York Medical College, Valhalla, NY, USA.
Mycopathologia. 2022 Dec;187(5-6):527-534. doi: 10.1007/s11046-022-00656-3. Epub 2022 Nov 10.
Candida auris is a nosocomial fungal pathogen of prime importance due to its global emergence and rapid spread in healthcare facilities worldwide. One important concern is that routine, conventional methods fail to identify C. auris. While molecular and protein-based assays accurately detect/identify C. auris, these methods are time-consuming, expensive, and require expertise. Therefore, the objective of the present study was to assess the potential use of a novel chromogenic medium, CHROMagar™ Candida Plus, as an economical alternative to expensive and laborious diagnostic tests. We compared CHROMagar™ Candida Plus with the standard enrichment (salt Sabouraud Dulcitol broth) medium to test the recovery efficiency of C. auris from surveillance samples. We also tested CHROMagar™ Candida Plus for its ability to distinguish C. auris from other yeast species. One hundred surveillance samples were cultured on CHROMagar™ Candida Plus and Dulcitol broth and incubated at 37 °C and 40 °C, respectively. Additionally, 32 Candida and yeast species were cultured on CHROMagar™ Candida Plus at 37 °C for three days to rule out any close resemblance to C. auris. Of 100 surveillance samples tested, 69 yielded presumptive positive C. auris exhibiting creamy pink colonies with a blue halo on CHROMagar™ Candida Plus within three days of incubation, and MALDI-TOF MS confirmed all by day 4. On the other hand, 69 of 100 surveillance samples yielded turbidity in Dulcitol broth by days 3-14 with final MALDI identification by days 5 to 17. Both media failed to identify one sample each, resulting in assay sensitivity and specificity of 99% and 97%, respectively. Of Candida and yeast species tested, 75-80% of C. metapsilosis and C. orthospilosis were misidentified as C. auris. However, previous studies indicated that these species are rarely detected in surveillance screening of C. auris. Naganishia diffluens also resembled C. auris, although it required different temperature growth (30 °C). In conclusion, CHROMagar™ Candida Plus provides rapid presumptive identification of C. auris. It would be another valuable tool in surveillance efforts to control the spread of C. auris in healthcare.
耳念珠菌是一种重要的医院真菌病原体，因为它在全球范围内的出现和在世界各地医疗机构的快速传播。一个重要的问题是，常规的传统方法无法识别耳念珠菌。虽然基于分子和蛋白质的检测方法能够准确地检测/识别耳念珠菌，但这些方法耗时、昂贵，且需要专业知识。因此，本研究的目的是评估一种新型显色培养基 CHROMagar™ Candida Plus 是否可作为昂贵且繁琐的诊断检测的经济替代方法。我们比较了 CHROMagar™ Candida Plus 与标准增菌（盐沙氏葡萄糖肉汤）培养基，以测试耳念珠菌从监测样本中的回收效率。我们还测试了 CHROMagar™ Candida Plus 区分耳念珠菌与其他酵母种的能力。将 100 份监测样本分别接种于 CHROMagar™ Candida Plus 和沙氏葡萄糖肉汤中，分别在 37°C 和 40°C 下孵育。此外，在 37°C 下培养 32 种念珠菌和酵母种，培养三天，以排除与耳念珠菌的任何相似之处。在测试的 100 份监测样本中，有 69 份在接种 CHROMagar™ Candida Plus 后三天内产生了奶油粉色的推定阳性耳念珠菌菌落，带有蓝色晕圈，MALDI-TOF MS 在第四天确认了所有样本。另一方面，100 份监测样本中有 69 份在沙氏葡萄糖肉汤中在第 3 天至第 14 天出现浑浊，最终 MALDI 鉴定在第 5 天至第 17 天完成。两种培养基都未能识别出各一份样本，因此检测的灵敏度和特异性分别为 99%和 97%。在所测试的念珠菌和酵母种中，75-80%的近平滑念珠菌和中间型念珠菌被错误鉴定为耳念珠菌。然而，之前的研究表明，这些种在耳念珠菌监测筛查中很少被检测到。异枝隔孢酵母也类似于耳念珠菌，尽管它需要不同的温度生长（30°C）。总之，CHROMagar™ Candida Plus 可快速初步鉴定耳念珠菌。它将成为控制耳念珠菌在医疗保健中传播的监测工作中的另一个有价值的工具。
