Shrestha Nabin K, Lim Sung H, Wilson Deborah A, SalasVargas Ana Victoria, Churi Yair S, Rhodes Paul A, Mazzone Peter J, Procop Gary W
Department of Infectious Diseases, Medicine Institute, Cleveland Clinic, Cleveland, Ohio, United States of America.
Department of Clinical Pathology, Pathology and Laboratory Medicine Institute, Cleveland Clinic, Cleveland, Ohio, United States of America.
PLoS One. 2017 Mar 15;12(3):e0173130. doi: 10.1371/journal.pone.0173130. eCollection 2017.
A colorimetric sensor array (CSA) has been demonstrated to rapidly detect and identify bacteria growing in blood cultures by obtaining a species-specific "fingerprint" of the volatile organic compounds (VOCs) produced during growth. This capability has been demonstrated in prokaryotes, but has not been reported for eukaryotic cells growing in culture. The purpose of this study was to explore if a disposable CSA could differentially identify 7 species of pathogenic yeasts growing in blood culture.
Culture trials of whole blood inoculated with a panel of clinically important pathogenic yeasts at four different microorganism loads were performed. Cultures were done in both standard BacT/Alert and CSA-embedded bottles, after adding 10 mL of spiked blood to each bottle. Color changes in the CSA were captured as images by an optical scanner at defined time intervals. The captured images were analyzed to identify the yeast species. Time to detection by the CSA was compared to that in the BacT/Alert system.
One hundred sixty-two yeast culture trials were performed, including strains of several species of Candida (Ca. albicans, Ca. glabrata, Ca. parapsilosis, and Ca. tropicalis), Clavispora (synonym Candida) lusitaniae, Pichia kudriavzevii (synonym Candida krusei) and Cryptococcus neoformans, at loads of 8.2 × 105, 8.3 × 103, 8.5 × 101, and 1.7 CFU/mL. In addition, 8 negative trials (no yeast) were conducted. All negative trials were correctly identified as negative, and all positive trials were detected. Colorimetric responses were species-specific and did not vary by inoculum load over the 500000-fold range of loads tested, allowing for accurate species-level identification. The mean sensitivity for species-level identification by CSA was 74% at detection, and increased with time, reaching almost 95% at 4 hours after detection. At an inoculum load of 1.7 CFU/mL, mean time to detection with the CSA was 6.8 hours (17%) less than with the BacT/Alert platform.
The CSA combined rapid detection of pathogenic yeasts in blood culture with accurate species-level identification.
已证明比色传感器阵列（CSA）通过获取生长过程中产生的挥发性有机化合物（VOCs）的物种特异性“指纹”，能够快速检测和识别血培养中生长的细菌。这种能力在原核生物中已得到证明，但在培养的真核细胞中尚未见报道。本研究的目的是探讨一次性CSA是否能够区分鉴定血培养中生长的7种致病性酵母。
在四种不同微生物载量下，对接种了一组临床重要致病性酵母的全血进行培养试验。在向每个瓶子中加入10 mL加标血液后，在标准BacT/Alert瓶和嵌入CSA的瓶子中进行培养。在规定的时间间隔，用光学扫描仪将CSA中的颜色变化捕获为图像。对捕获的图像进行分析以鉴定酵母种类。将CSA的检测时间与BacT/Alert系统的检测时间进行比较。
进行了162次酵母培养试验，包括几种念珠菌（白色念珠菌、光滑念珠菌、近平滑念珠菌和热带念珠菌）、葡萄牙棒孢酵母（同义词念珠菌）、季也蒙毕赤酵母（同义词克鲁斯念珠菌）和新型隐球菌的菌株，载量分别为8.2×105、8.3×103、8.5×101和1.7 CFU/mL。此外，进行了8次阴性试验（无酵母）。所有阴性试验均被正确鉴定为阴性，所有阳性试验均被检测到。比色反应具有物种特异性，在所测试的500000倍载量范围内，不会因接种物载量而变化，从而能够进行准确的物种水平鉴定。CSA进行物种水平鉴定的平均灵敏度在检测时为74%，并随时间增加，在检测后4小时达到近9%。在接种物载量为1.7 CFU/mL时，CSA的平均检测时间比BacT/Alert平台少6.8小时（17%）。
CSA将血培养中致病性酵母的快速检测与准确的物种水平鉴定相结合。
