Multicenter Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry Study for Identification of Clinically Relevant Nocardia spp.
Multicenter Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry Study for Identification of Clinically Relevant Nocardia spp.
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DOI：
10.1128/jcm.02942-15
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发表时间：
2016-05-01
影响因子：
9.4
通讯作者：
Zelazny, Adrian M.
中科院分区：
文献类型：
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作者：
Blosser, Sara J.;Drake, Steven K.;Zelazny, Adrian M.
这项多中心研究分析了诺卡迪亚菌，包括提取、光谱采集、布鲁克矩阵辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）鉴定和评分解释，使用了三个诺卡迪亚文库，布鲁克、美国国立卫生研究院（NIH）和俄亥俄州立大学（OSU）文库，并比较了每个中心获得的结果。标准化研究方案、150株诺卡菌分离株、NIH和OSU诺卡菌MALDI-TOF质谱文库被分发到三个中心。经过标准化培养、提取和MALDI-TOF MS分析，分离物的鉴定采用>= 2.0的分值截断值进行种/种复合体鉴定，>= 1.8的分值截断值用于属水平鉴定。对评分< 2.0的分离株进行单次重复提取和分析。所有中心的总体得分范围为1.3 ~ 2.7（平均2.2 +/- 0.3），常见物种的平均得分普遍高于不常见物种。评分分类和分离鉴定中心间的一致性为86%；150株分离物中，118株在种/种复合体水平上鉴定正确。9株（6.0%）未被中心鉴定，6株（4.0%）为罕见种，文库代表性有限。中心间出现21株（14.0%）分类评分差异。重复提取低评分分离株的总体效益为21.2%，重复斑点的中心依赖效益（范围为2%至8.7%）。最后，与OSU和NIH文库相结合的Bruker Nocardia MALDI-TOF MS文库分别提高了18.2%和36.9%的属水平和种水平鉴定。总体而言，本研究证明了不同临床微生物实验室利用MALDI-TOF质谱快速鉴定临床相关诺卡菌的能力，以及跨机构单个实验室开发的MALDI-TOF质谱文库的能力。
This multicenter study analyzed Nocardia spp., including extraction, spectral acquisition, Bruker matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) identification, and score interpretation, using three Nocardia libraries, the Bruker, National Institutes of Health (NIH), and The Ohio State University (OSU) libraries, and compared the results obtained by each center. A standardized study protocol, 150 Nocardia isolates, and NIH and OSU Nocardia MALDI-TOF MS libraries were distributed to three centers. Following standardized culture, extraction, and MALDI-TOF MS analysis, isolates were identified using score cutoffs of >= 2.0 for species/species complex-level identification and >= 1.8 for genus-level identification. Isolates yielding a score of < 2.0 underwent a single repeat extraction and analysis. The overall score range for all centers was 1.3 to 2.7 (average, 2.2 +/- 0.3), with common species generally producing higher average scores than less common ones. Score categorization and isolate identification demonstrated 86% agreement between centers; 118 of 150 isolates were correctly identified to the species/species complex level by all centers. Nine strains (6.0%) were not identified by any center, and six (4.0%) of these were uncommon species with limited library representation. A categorical score discrepancy among centers occurred for 21 isolates (14.0%). There was an overall benefit of 21.2% from repeat extraction of low-scoring isolates and a center-dependent benefit for duplicate spotting (range, 2 to 8.7%). Finally, supplementation of the Bruker Nocardia MALDI-TOF MS library with both the OSU and NIH libraries increased the genus-level and species-level identification by 18.2% and 36.9%, respectively. Overall, this study demonstrates the ability of diverse clinical microbiology laboratories to utilize MALDI-TOF MS for the rapid identification of clinically relevant Nocardia spp. and to implement MALDI-TOF MS libraries developed by single laboratories across institutions.