Hu Ya-Li, Hsueh Shun-Chung, Ding Guan-Syun, Chuang Pei-Chien, Chen Jong-Min, Lu Chun-Yi, Chang Luan-Yin, Huang Li-Min, Lee Ping-Ing, Hsueh Po-Ren
Department of Pediatrics, New Taipei City Hospital, New Taipei City, Taiwan.
Department of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
J Microbiol Immunol Infect. 2020 Dec;53(6):916-924. doi: 10.1016/j.jmii.2020.01.004. Epub 2020 Feb 13.
BACKGROUND/PURPOSE: Early identification of pathogens causing bloodstream infection (BSI) is critical for prompt administration of appropriate antimicrobial therapy.
We used an in-house saponin-based extraction method to evaluate the performance of Bruker Biotyper MALDI-TOF MS system (MALDI Biotyper) for bacterial and fungal identification in 2013 positively-flagged VersaTREK blood culture bottles.
A total of 180 monomicrobial and 23 polymicrobial positive blood cultures were investigated. Among monomicrobial positive blood cultures, the MALDI Biotyper recognized 90.6% and 81.7% of organisms directly from the flagged blood culture bottles to the genus and species levels, respectively. The MALDI Biotyper also correctly characterized one of the polymicrobial organisms to the species level in 20 (87%) bottles and to the genus level in 21 (91.3%) bottles. The overall identification rate using our protocol was 90.6% (184/203) and 82.3% (167/203) for genus and species levels, respectively. Identification accuracy was higher for Gram-positive than Gram-negative organisms and was the lowest for yeasts. Score values of identification were ≥1.500 for 200 (98.5%) bottles, ≥1.700 for 195 (96.1%) bottles and ≥2.000 for 182 (89.7%) bottles. Moreover, 83.5% and 92% of the isolates were identified precisely to species and genus level with the lower cutoff score of 1.500. Using our protocol also helped identifying BSI pathogens 18-24 h earlier compared to the sub-cultured colonies.
Using Bruker MALDI Biotyper for identification of isolates directly from positive VersaTREK blood culture bottles, our in-house saponin-based protocol provided a more rapid turn-around time for correct identification of BSI pathogens than the conventional methods.
背景/目的：早期识别引起血流感染（BSI）的病原体对于及时给予适当的抗菌治疗至关重要。
2013年，我们使用一种基于皂苷的内部提取方法，评估布鲁克微生物鉴定飞行时间质谱系统（MALDI Biotyper）在VersaTREK血培养瓶阳性样本中进行细菌和真菌鉴定的性能。
共研究了180份单微生物阳性和23份多微生物阳性血培养样本。在单微生物阳性血培养样本中，MALDI Biotyper分别直接从标记的血培养瓶中将90.6%和81.7%的微生物鉴定到属和种水平。MALDI Biotyper还在20份（87%）培养瓶中将一种多微生物样本正确鉴定到种水平，在21份（91.3%）培养瓶中将其鉴定到属水平。使用我们的方案，属水平和种水平的总体鉴定率分别为90.6%（184/203）和82.3%（167/203）。革兰氏阳性菌的鉴定准确率高于革兰氏阴性菌，酵母菌的鉴定准确率最低。200份（98.5%）培养瓶的鉴定分值≥1.500，195份（96.1%）培养瓶的鉴定分值≥1.700，182份（89.7%）培养瓶的鉴定分值≥2.000。此外，83.5%和92%的分离株在较低的截断分值1.500时被精确鉴定到种和属水平。与传代培养菌落相比，使用我们的方案还能提前18 - 24小时鉴定出BSI病原体。
使用布鲁克MALDI Biotyper直接从VersaTREK血培养瓶阳性样本中鉴定分离株，我们基于皂苷的内部方案比传统方法能更快地正确鉴定BSI病原体。
