Objective

The aim was to evaluate a rapid method which would combine identification and susceptibility testing directly from positive blood cultures for Gram-negative bacilli of the Enterobacterales.

Material and methods

Gram-negative rods from blood cultures were directly identified by MALDI-TOF. Samples with Enterobacterales were selected for direct antimicrobial susceptibility testing by Vitek 2. The results were compared to those obtained with our laboratory's standard method.

Results

MALDI-TOF directly from blood cultures identified correctly 83% of the samples. Enterobacterales (n = 68) were identified at gender and species level in 85% of blood cultures with a score >1.7. In general, MICs were obtained after 7 h. MICs of amoxicillin-clavulanate, amikacin and ciprofloxacin showed in almost 50% of the cases after 5 h.

Conclusions

A simple procedure with low cost and reduced working time makes it possible to integrate both identification and susceptibility testing directly from blood cultures. Thus, this protocol could offer advantages when it comes to selection and cost of treatment and patients’ clinical outcomes.

中文翻译：

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质谱法和 Vitek 2 组合方案的评估，用于直接从阳性血培养物中快速鉴定和敏感性测试的肠杆菌。

客观的

目的是评估一种快速方法，该方法将直接从阳性血培养中对肠杆菌属革兰氏阴性杆菌进行鉴定和药敏试验相结合。

材料与方法

通过 MALDI-TOF 直接鉴定来自血培养的革兰氏阴性杆菌。通过 Vitek 2 选择含有肠杆菌的样品进行直接的抗菌药敏感性测试。将结果与我们实验室的标准方法获得的结果进行比较。

结果

直接来自血培养的 MALDI-TOF 正确识别了 83% 的样本。肠杆菌 ( n  = 68) 在 85% 的血培养物中在性别和物种水平上被鉴定，得分 >1.7。一般来说，MIC 是在 7 小时后获得的。阿莫西林-克拉维酸、阿米卡星和环丙沙星的 MIC 在 5 小时后显示在几乎 50% 的病例中。

结论

成本低、工作时间短的简单程序使得直接从血培养中整合鉴定和敏感性测试成为可能。因此，该协议在治疗的选择和成本以及患者的临床结果方面具有优势。