Penven Malo, Louazon Manon, Freret Charlotte, Sauron Alexandra, Pilard Meghane, Creignou Elisa, Gardan Ophélie, Haumont Maryne, Zouari Asma, Lorre Stéphane, Cattoir Vincent
Department of Bacteriology, Rennes University Hospital, Rennes, France.
UMR_S1230 Inserm BRM, University of Rennes, Rennes, France.
J Clin Microbiol. 2025 Feb 19;63(2):e0133224. doi: 10.1128/jcm.01332-24. Epub 2024 Dec 20.
Rapid and accurate diagnosis of sepsis is of paramount importance to reduce associated morbidity and mortality. The Qvella FAST System is a new instrument that concentrates and purifies bacteria from positive-flagged blood culture bottles (PFBCBs) to produce a "liquid" colony comparable to a subcultured colony in less than 40 min for rapid ID and calibrated antibiotic susceptibility testing (AST). In this study, we evaluated performances of the FAST System workflow and our rapid routine manual workflow (bacterial pellet obtained after lysis, cleaning, washing, and centrifugation for ID; AST by disc diffusion by direct inoculation after dilution) by comparison to the reference method based on 24-h bacterial subcultures. Two panels of PFBCBs were studied: panel A (including 107 prospective BCs from septic patients, October-November 2022) and panel B (including 102 BCs spiked with difficult-to-identify bacteria [mostly streptococci] and multidrug-resistant isolates), resulting in a total of 209 evaluable samples. The FAST System provided a correct ID to the species level in 178/209 (85.2%) of cases. For AST, the categorical agreement (CA) of the FAST System was 99.4%, with rates of very major (VME), major (ME), and minor (mE) errors of 0.59%, 0.20%, and 0.26%, respectively. Our rapid routine workflow based on manual methods show similar results for ID (86.2%) and AST (CA, 99.6%; VME, 0.50%; ME, 0.16%; mE, 0.13%). In conclusion, the Qvella FAST system, a promising tool that can reduce diagnostic time by approximately 1 day, shows excellent performances for rapid ID and AST.
快速准确地诊断脓毒症对于降低相关的发病率和死亡率至关重要。Qvella FAST系统是一种新型仪器，可从阳性标记血培养瓶（PFBCB）中浓缩和纯化细菌，在不到40分钟的时间内产生一个与传代培养菌落相当的“液体”菌落，用于快速鉴定和校准抗生素敏感性测试（AST）。在本研究中，我们通过与基于24小时细菌传代培养的参考方法进行比较，评估了FAST系统工作流程和我们的快速常规手工工作流程（裂解、清洗、洗涤和离心后获得细菌沉淀用于鉴定；稀释后直接接种通过纸片扩散法进行AST）的性能。研究了两组PFBCB：A组（包括2022年10月至11月来自脓毒症患者的107份前瞻性血培养）和B组（包括102份接种了难鉴定细菌[主要是链球菌]和多重耐药菌株的血培养），总共209个可评估样本。FAST系统在178/209（85.2%）的病例中提供了到种水平的正确鉴定。对于AST，FAST系统的分类一致性（CA）为99.4%，极重大（VME）、重大（ME）和微小（mE）错误率分别为0.59%、0.20%和0.26%。我们基于手工方法的快速常规工作流程在鉴定（86.2%）和AST方面显示出相似的结果（CA，99.6%；VME，0.50%；ME，0.16%；mE，0.13%）。总之，Qvella FAST系统是一种有前景的工具，可将诊断时间缩短约1天，在快速鉴定和AST方面表现出色。
