Abstract：
This study aimed to assess the performance of our in-house method for rapid direct bacterial identification (ID) and antimicrobial susceptibility testing (AST) using a positive blood culture (BC) broth. For Gram-negative bacteria, 4 mL of BC broth was aspirated and passed through a Sartorius Minisart syringe filter with a pore size of 5 µm. The filtrate was then centrifuged and washed. A small volume of the pellet was used for ID, using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and for AST, using automated broth microdilution. For Gram-positive cocci, 4 mL of BC broth was passed through the Minisart syringe filter. Then, 4 mL of sterile distilled water was injected in the direction opposite to that of the filtration to collect the bacterial residue trapped in the filter. Compared with the conventional method performed with pure colonies on agar plates, 94.0% (234/249) were correctly identified using the in-house method, with rates of 91.4% (127/139) and 97.3% (107/110) for Gram-positive and Gram-negative isolates, respectively. Of 234 correctly identified isolates, 230 were assessed by AST. Categorical agreement and essential agreement were 93.3% and 94.5%, respectively, with a minor error rate of 3.8%, a major error rate of 3.4%, and a very major error rate of 1.6%. Our in-house preparation method showed good performance in rapid direct ID and AST using positive BC broths compared to the conventional method. This simple method can shorten the conventional turnaround time for ID and AST by at least 1 day, potentially contributing to better patient management.
摘要：
这项研究旨在评估使用阳性血培养（BC）肉汤进行快速直接细菌鉴定（ID）和抗菌敏感性测试（AST）的内部方法的性能。对于革兰氏阴性细菌，将4mL的BC肉汤吸出并通过孔径为5μm的SartoriusMinisart注射器过滤器。然后将滤液离心并洗涤。少量的颗粒用于ID，使用基质辅助激光解吸/电离飞行时间质谱，对于AST来说,使用自动肉汤微量稀释。对于革兰氏阳性球菌，使4mL的BC肉汤通过Minisart注射器过滤器。然后，以与过滤方向相反的方向注入4mL无菌蒸馏水以收集截留在过滤器中的细菌残留物。与在琼脂平板上使用纯菌落进行的常规方法相比，使用内部方法正确识别了94.0%(234/249)，革兰氏阳性和革兰氏阴性分离株的比率分别为91.4％（127/139）和97.3％（107/110），分别。在234个正确鉴定的分离株中，230通过AST评估。分类协议和基本协议分别为93.3%和94.5%，分别,轻微错误率为3.8%，主要错误率为3.4%，和1.6％的非常主要的错误率。与常规方法相比，我们的内部制备方法在使用阳性BC肉汤的快速直接ID和AST中显示出良好的性能。这种简单的方法可以将ID和AST的常规周转时间缩短至少1天，可能有助于更好的患者管理。
