Global Medical Affairs, bioMérieux, Lyon, France.
Global Medical Affairs, bioMérieux, Hazelwood, Missouri, USA.
Microbiol Spectr. 2024 Sep 3;12(9):e0381523. doi: 10.1128/spectrum.03815-23. Epub 2024 Jul 23.
Reliable detection of A and C-mediated beta-lactam resistance using automated antimicrobial susceptibility test systems is critical for patient care. The aim of this study was to compare the performance of the new cefoxitin screen test (oxsf02n) on the Vitek 2 card (Vitek 2) and BD Phoenix PMC-100 Gram-Positive AST Panel (Phoenix) against the reference method for the detection of A (and C)-mediated beta-lactam resistance. Two hundred fifty clinical fresh and stock spp. isolates were included. There were 120 A-positive, 10 C-positive, and 120 A and C-negative isolates. Cefoxitin screen and oxacillin tests were performed on Vitek 2 and Phoenix and by their respective reference methods (disk diffusion for the cefoxitin screen test and broth microdilution for oxacillin) for all isolates. PCR testing was also performed to confirm the presence of A and/or C genes. Results from each system were compared to the reference methods. Statistical hypotheses were evaluated both for Vitek 2 compared to the reference methods and Vitek 2 compared to the Phoenix. Compared to the reference method, the Vitek 2 cefoxitin screen test had 100% sensitivity/98% specificity and the Phoenix cefoxitin screen test had 84% sensitivity/100% specificity for the detection of A (and C)-mediated beta-lactam resistance. When the oxacillin test was combined with the cefoxitin screen for Vitek 2, the sensitivity and specificity were unchanged. However, when the oxacillin and cefoxitin screen tests were combined for the Phoenix, the sensitivity increased to 100% and the specificity remained unchanged (100%). When considering cefoxitin alone, the Vitek 2 screen test showed a higher sensitivity than the Phoenix for the detection of A and C-mediated beta-lactam resistance. However, currently, both systems use a combination of the cefoxitin and oxacillin tests to interpret the final result, and both reached a high level of performance when cefoxitin and oxacillin results were combined.IMPORTANCEThis research marks the inaugural evaluation of the revamped cefoxitin screen test version in Vitek 2, juxtaposing it against reference methods and a primary competitor BD Phoenix.
可靠地检测 A 和 C 介导的β-内酰胺耐药性对于患者护理至关重要。本研究的目的是比较新的头孢西丁筛选试验（oxsf02n）在 Vitek 2 卡（Vitek 2）和 BD Phoenix PMC-100 革兰阳性 AST 面板（Phoenix）上的性能，与检测 A（和 C）介导的β-内酰胺耐药性的参考方法进行比较。共纳入 250 例临床新鲜和库存 spp. 分离株。其中 120 株为 A 阳性，10 株为 C 阳性，120 株为 A 和 C 阴性。对所有分离株在 Vitek 2 和 Phoenix 上进行头孢西丁筛选试验和苯唑西林试验，并通过各自的参考方法（头孢西丁筛选试验为纸片扩散法，苯唑西林为肉汤微量稀释法）进行检测。还进行了 PCR 检测以确认 A 和/或 C 基因的存在。将每个系统的结果与参考方法进行比较。评估了 Vitek 2 与参考方法比较和 Vitek 2 与 Phoenix 比较的统计假设。与参考方法相比，Vitek 2 头孢西丁筛选试验对 A（和 C）介导的β-内酰胺耐药性的检测具有 100%的敏感性/98%的特异性，而 Phoenix 头孢西丁筛选试验的敏感性为 84%，特异性为 100%。当将苯唑西林试验与 Vitek 2 的头孢西丁筛选试验结合使用时，敏感性和特异性保持不变。然而，当将苯唑西林和头孢西丁筛选试验结合用于 Phoenix 时，敏感性提高到 100%，特异性保持不变（100%）。单独考虑头孢西丁时，Vitek 2 筛选试验对检测 A 和 C 介导的β-内酰胺耐药性的敏感性高于 Phoenix。然而，目前，两个系统都使用头孢西丁和苯唑西林试验的组合来解释最终结果，当头孢西丁和苯唑西林的结果组合使用时，两个系统都达到了较高的性能水平。
重要性 本研究首次评估了 Vitek 2 中新修订的头孢西丁筛选试验版本，将其与参考方法和主要竞争对手 BD Phoenix 进行了比较。
