Ugaban Khay, Pak Pil, She Rosemary C
Keck Medical Center, University of Southern California, Los Angeles, CA 90033, USA.
Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
Microorganisms. 2022 Oct 20;10(10):2076. doi: 10.3390/microorganisms10102076.
Bloodstream infections are a leading cause of morbidity and mortality. The rapid diagnostic testing of positive blood cultures (PBCs) shortens times to effective therapy and the de-escalation of broad-spectrum empiric therapy. This is the first study examining the Qvella FAST System for the rapid (~20 min) purification of microorganisms directly from PBCs using BacT/Alert FA/FAN bottles in the bioMérieux Virtuo instrument. We compared the performance of the FAST System Liquid Colony (LC), for immediate downstream ID and phenotypic AST, to standard workflow involving colonies obtained by overnight subculture. The LC yielded a concordant species ID by VITEK MS in 121/138 (87.7%) samples, identifying 32 different Gram-positive and Gram-negative species with 3/123 (2.6%) discordances. Compared to standard workflow, direct AST of the LC using VITEK 2 yielded 98.4% categorical agreement and 98.0% essential agreement. Very major error, major error, and minor error rates were 1.0%, 0.0%, and 1.8%, respectively, for Gram-negative organisms; and 1.9%, 0.2%, and 1.2%, respectively, for Gram-positive organisms. The median times from positive blood culture flag to results by FAST System for ID and AST were 7.8 h and 15.7 h, respectively, versus 22.4 h and 36.6 h for standard workflow, respectively. In conclusion, the FAST System provides reliable results for direct ID and AST from PBCs with significantly decreased turnaround times.
血流感染是发病和死亡的主要原因。对阳性血培养（PBC）进行快速诊断检测可缩短有效治疗时间并减少广谱经验性治疗的降级。这是第一项研究Qvella FAST系统，该系统使用生物梅里埃Virtuo仪器中的BacT/Alert FA/FAN瓶直接从PBC中快速（约20分钟）纯化微生物。我们将FAST系统液体菌落（LC）用于直接下游鉴定和表型药敏试验（AST）的性能与涉及通过过夜传代培养获得菌落的标准工作流程进行了比较。LC在121/138（87.7%）的样本中通过VITEK MS产生了一致的菌种鉴定结果，鉴定出32种不同的革兰氏阳性和革兰氏阴性菌种，有3/123（2.6%）的不一致情况。与标准工作流程相比，使用VITEK 2对LC进行直接AST产生了98.4%的类别一致性和98.0%的基本一致性。革兰氏阴性菌的极重大错误率、重大错误率和微小错误率分别为1.0%、0.0%和1.8%；革兰氏阳性菌的分别为1.9%、0.2%和1.2%。FAST系统进行鉴定和AST从阳性血培养标记到结果的中位时间分别为7.8小时和15.7小时，而标准工作流程分别为22.4小时和36.6小时。总之,FAST系统为直接从PBC进行鉴定和AST提供了可靠的结果，显著缩短了周转时间。
