Timely diagnosis of microorganisms in blood cultures is necessary to optimize therapy. Although blood culture media and systems have evolved for decades, the standard interval for incubation prior to being discarded as negative has remained 5 days. Here, we evaluated the optimal incubation time for the BacT/Alert Virtuo blood culture detection system (bioMérieux) using FA Plus (aerobic) and FN Plus (anaerobic) resin culture bottles in routine clinical use. Following institutional review board (IRB) approval, a retrospective review evaluated the outcomes of 158,710 bottles collected between November 2018 and October 2019. The number of positive blood bottles was 13,592 (8.6%); 99% of positive aerobic and anaerobic bottles flagged positive by 91.5 and 108 h, respectively. The mean (median) times to positivity were 18.4 h (15.6 h) for Staphylococcus aureus, 12.3 h (9.5 h) for Escherichia coli, 22.2 h (15.9 h) for Pseudomonas aeruginosa, and 48.9 h (42.9 h) for Candida spp. Only 175 bottles (0.1% of all bottles) flagged positive after 4 days of incubation; 89 (51%) of these bottles grew Cutibacterium (Propionibacterium) species. Chart review of blood cultures positive after 4 days (96 h) rarely had a clinical impact and sometimes had a negative impact on patient care. Finally, a seeded study of the HACEK group (i.e., Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, and Kingella), historically associated with delayed blood culture positivity, demonstrated no benefit to extended incubation beyond 4 days. Collectively, these findings demonstrated that a 4-day incubation time was sufficient for the Virtuo system and media. Implementation of the 4-day incubation time could enhance clinically relevant results by reducing recovery of contaminants and finalizing blood cultures 1 day earlier.

中文翻译：

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评估最佳血液培养温育时间，以最大程度地利用当代血液培养仪器和培养基系统获得临床相关结果

及时诊断血液培养物中的微生物是优化治疗的必要条件。尽管血液培养基和系统已经发展了数十年，但在丢弃为阴性之前的标准孵育时间间隔仍为5天。在这里，我们评估了在常规临床应用中使用FA Plus（需氧）和FN Plus（厌氧）树脂培养瓶对BacT / Alert Virtuo血液培养检测系统（bioMérieux）的最佳孵育时间。在机构审查委员会（IRB）批准之后，回顾性评估评估了2018年11月至2019年10月收集的158,710瓶的结果。阳性血液瓶数量为13,592（8.6％）；阳性需氧和厌氧瓶分别有91.5和108 h标记为阳性。男性的平均（中位数）时间为18.4小时（15.6小时）金黄色葡萄球菌，大肠杆菌12.3 h（9.5 h），铜绿假单胞菌22.2 h（15.9 h），假丝酵母（Candida spp ）48.9 h（42.9 h）。孵育4天后，只有175瓶（占所有瓶子的0.1％）标记为阳性；这些瓶子中有89（51％）种是角皮杆菌（Propionibacterium）种。4天（96小时）后血培养呈阳性的图表检查很少对临床产生影响，有时对患者护理产生不利影响。最后，HACEK组的种子研究（即，流感嗜血杆菌，Aggregatibacter，Cardiobacterium，Eikenella和金氏），从历史上讲与血液培养的阳性反应延迟有关，证明延长培养超过4天没有好处。总的来说，这些发现表明，对于Virtuo系统和培养基而言，4天的孵育时间足够了。4天孵育时间的实施可以通过减少污染物的回收并提前1天完成血液培养来增强临床相关结果。