Routine identification and mixed species detection in 6,192 clinical yeast isolates
Routine identification and mixed species detection in 6,192 clinical yeast isolates
复制标题
DOI：
10.1093/mmy/myv095
复制
发表时间：
2016-03-01
期刊：
影响因子：
2.9
通讯作者：
Piarroux, Renaud
中科院分区：
文献类型：
--
作者：
Cassagne, Carole;Normand, Anne-Cecile;Piarroux, Renaud
用于诊断酵母菌感染的临床实验室方法应该是快速、可靠的，并能够检测出具有明显抗真菌敏感性特征的物种的混合感染。在这项研究中，我们报告了一种将检测混合酵母培养物与显色介质和MALDI-TOF鉴定菌落相结合的程序。然后，我们在常规实验室中评估了(I)分离介质和(Ii)降低鉴定日志分数(LS)阈值对酵母菌鉴定性能的影响。在分析的15,661份临床样本中，有5,671份检测呈阳性，42个不同物种的6,192株酵母得到鉴定。总体而言，在第一次或第二次MALDI-TOF质谱分析(MS)中鉴定出6,117个菌株(98.79%)，平均酵母物种鉴定周转时间为0.346天(95%CI[0.326至0.364])。对其余75株进行了核苷酸序列测定。混合感染占阳性标本的498例(8.78%)。无论采用何种培养介质，MALDI-TOF MS鉴定程序都表现良好。将推荐的2.0 LS阈值降低到1.8将减少所需的次数(I)二次MALDI-TOF MS鉴定尝试(178对490)和(Ii)基于ITS2和D1-D2序列的鉴定(17对75)，同时获得足够的识别率(6,183/6,192，99.85%)。
The clinical laboratory methods used to diagnose yeast infections should be rapid, reliable, and capable of detecting mixed infections with species exhibiting a distinct antifungal susceptibility profile. In this study, we report the performance of a procedure combining the detection of mixed yeast cultures with a chromogenic medium and MALDI-TOF identification of the colonies. We then evaluated the impact that (i) the isolation medium and (ii) lowering the identification log score (LS) threshold value have on yeast identification performance in the routine laboratory.Among 15,661 clinical samples analyzed, 5,671 tested positive and 6,192 yeasts of 42 distinct species were identified. Overall, 6,117 isolates (98.79%) were identified on the first or second MALDI-TOF Mass Spectrometry (MS) attempt, yielding an average yeast species identification turnaround time of 0.346 days (95% CI [0.326 to 0.364]). The 75 remaining isolates were identified via nucleotide sequencing. Mixed infections accounted for 498 (8.78%) of the positive samples. The MALDI-TOF MS identification procedure performed well, regardless of the culture media tested. Lowering the recommended 2.0 LS threshold value to 1.8 would reduce the number of required (i) second MALDI-TOF MS identification attempts (178 vs. 490) and (ii) ITS2 and D1-D2 sequence-based identifications (17 vs. 75), while achieving an adequate identification rate (6,183/6,192, 99.85%).In conclusion, we propose applying a 1.8 LS threshold combined with chromogenic medium subculture to optimize the yeast identification workflow and detect mixed infection in the clinical laboratory.