Department for Infectious Diseases, University Hospital Heidelberg, Heidelberg, Germany.
Eur J Clin Microbiol Infect Dis. 2020 Jul;39(7):1305-1313. doi: 10.1007/s10096-020-03846-3. Epub 2020 Feb 28.
Our objective was to evaluate EUCAST's 'rapid antimicrobial susceptibility testing' (RAST) directly from positive blood culture that delivers antimicrobial results within 6 h for Staphylococcus aureus, Enterococcus spp., Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa, using total lab automation. Zone diameters from RAST were compared with MIC results. Furthermore, its influence on time to report was investigated. RAST was performed to all positive aerobic and anaerobic blood culture bottles by subculturing them, i.e. onto Mueller-Hinton agar and adding six antibiotic discs covering Gram-negative and Gram-positive therapy (cefoxitin, ampicillin, vancomycin, piperacillin/tazobactam, meropenem and ciprofloxacin). RAST was automatically imaged after 6 h. Zone sizes were measured using a TLA software tool and interpreted according to EUCAST clinical breakpoints. Bacteria were identified using MALDI-TOF MS and MIC results were determined using Vitek2 panels. Categorial agreement between agar diffusion and MIC results was investigated. Additionally, time to RAST and time to Vitek were compared for 100 isolates (20 per species). Between November 2018 and April 2019, 3313 positive mono-bacterial blood culture bottles were collected of which 894 bottles with RAST-validated species were investigated. Among these bottles, 2029 individual antibiotic measurements were compared with MIC results from Vitek2 and 14 very major, 28 major and 12 minor errors were found. A median reduction of 17:30 h in time to report was observed. Introduction of RAST with automatic TLA imaging function could reduce time to report by 17:30 h. Excellent accordance between zone diameter and MIC results, particularly for cefoxitin, vancomycin and meropenem, was observed, but drawbacks due to ATU were seen.
我们的目标是使用全自动实验室评估 EUCAST 的“快速抗菌药敏试验”（RAST），该方法可在 6 小时内直接从阳性血培养物中得到金黄色葡萄球菌、肠球菌属、大肠埃希菌、肺炎克雷伯菌和铜绿假单胞菌的抗菌结果。RAST 的药敏结果与 MIC 结果进行比较。此外，还研究了其对报告时间的影响。对所有阳性需氧和厌氧血培养瓶进行 RAST 检测，通过传代培养，即将其接种到 Mueller-Hinton 琼脂上，并添加六张涵盖革兰氏阴性和革兰氏阳性治疗的抗生素药敏纸片（头孢西丁、氨苄西林、万古霉素、哌拉西林/他唑巴坦、美罗培南和环丙沙星）。RAST 自动在 6 小时后进行成像。使用 TLA 软件工具测量抑菌环直径，并根据 EUCAST 临床折点进行解释。使用 MALDI-TOF MS 进行细菌鉴定，使用 Vitek2 药敏板确定 MIC 结果。评估琼脂扩散和 MIC 结果的分类一致性。此外，还对 100 株（每种 20 株）的 RAST 和 Vitek2 时间进行了比较。2018 年 11 月至 2019 年 4 月，共收集了 3313 份阳性单瓶血培养物，其中 894 份经 RAST 验证的瓶进行了研究。在这些瓶中，2029 个单独的抗生素测量值与 Vitek2 的 MIC 结果进行了比较，发现了 14 个非常大、28 个大和 12 个小错误。报告时间平均缩短了 17:30 小时。引入 RAST 并结合自动 TLA 成像功能可将报告时间缩短 17:30 小时。抑菌环直径和 MIC 结果之间具有极好的一致性，特别是头孢西丁、万古霉素和美罗培南，但是由于自动接种技术（ATU）也存在一些缺陷。
