Dai Yufeng, Xu Xinyi, Yan Xue, Li Daming, Cao Wei, Tang Lingli, Hu Min, Jiang Chuanhao
Department of Laboratory Medicine, The Second Xiangya Hospital, Central South University, Changsha, China.
Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, China.
Front Cell Infect Microbiol. 2021 Mar 11;11:632679. doi: 10.3389/fcimb.2021.632679. eCollection 2021.
Early and rapid identification of microorganisms is critical for reducing the mortality rate caused by bloodstream infections (BSIs). The accuracy and feasibility of directly identifying pathogens in positive blood cultures by matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been intensely confirmed. In this study, we combined density centrifugation and extra chemical lysis-extraction to develop an optimized method in the blood culture process, which significantly improved the effectiveness of direct identification by MALDI-TOF MS. The accuracy was evaluated by 2,032 positive blood culture samples (115 species of microorganism). The overall MALDI-TOF MS based identification rate with scores ≥ 1.700 was 87.60%. 94.06% of gram-negative bacteria were identified consistently to the genus level, followed by anaerobes (93.33%), gram-positive bacteria (84.46%), and fungi (60.87%). This protocol could obtain results within 10-20 min at a cost of less than $0.1 per sample, which saved up to 24 h in identifying 87.60% of the microorganism from positive blood cultures. This rapid and simplified protocol facilitates the direct identification of microorganism in positive blood cultures, and exhibits the advantages of cost-effective, time-saving, and easy-to-use. It could provide the causative organism of the patient to clinicians in time for targeted treatment and reduce mortality.
早期快速鉴定微生物对于降低血流感染（BSIs）导致的死亡率至关重要。基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）直接鉴定阳性血培养物中病原体的准确性和可行性已得到充分证实。在本研究中，我们将密度离心与额外的化学裂解提取相结合，在血培养过程中开发了一种优化方法，显著提高了MALDI-TOF MS直接鉴定的有效性。通过2032份阳性血培养样本（115种微生物）评估准确性。基于MALDI-TOF MS且得分≥1.700的总体鉴定率为87.60%。94.06%的革兰氏阴性菌在属水平上得到一致鉴定，其次是厌氧菌（93.33%）、革兰氏阳性菌（84.46%）和真菌（60.87%）。该方案可在10 - 20分钟内获得结果，每个样本成本低于0.1美元，从阳性血培养物中鉴定87.60%的微生物最多可节省24小时。这种快速且简化的方案有助于直接鉴定阳性血培养物中的微生物，具有成本效益高、省时且易于使用的优点。它可以及时为临床医生提供患者的致病微生物，以便进行针对性治疗并降低死亡率。
