Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain.
Red Española de Investigación en Patología Infecciosa (REIPI), Madrid, Spain.
J Clin Microbiol. 2020 Jan 28;58(2). doi: 10.1128/JCM.01042-19.
Piperacillin-tazobactam (P/T) is a β-lactam-β-lactamase inhibitor combination frequently used in the hospital setting. Etest is a gradient diffusion method that represents an alternative to broth microdilution (BMD) for performing antimicrobial susceptibility testing. We conducted a multicenter evaluation of the performance of the new P/T Etest compared to that of BMD following U.S. Food and Drug Administration (FDA) and International Standards Organization (ISO) standard ISO 20776-2 criteria using Clinical and Laboratory Standards Institute (CLSI)-FDA and European Committee on Antimicrobial Susceptibility Testing (EUCAST) interpretive breakpoints, respectively. A total of 977 isolates (775 isolates, 119 isolates, and 83 complex isolates) were tested. Overall essential agreement (EA) was 96.4% and 96.6% for when FDA and ISO 20776-2 criteria, respectively, were followed. EA was 98.3% for and 91.6% for the complex when both the FDA and ISO criteria were followed. Applying CLSI-FDA breakpoints, categorical agreement (CA) reached 93.0%, 93.3%, and 89.2% for the , , and the complex, respectively. Two very major errors (VMEs; 1.1%) were found among the (for 2 isolates). No additional major errors (MEs) or VMEs were found. Applying EUCAST breakpoints, CA was 94.8% and 95.8% for and , respectively (no breakpoints are currently available for the complex). No VMEs were observed among the , but 2 (0.4%) MEs were found. Among the isolates, 2 (6.9%) VMEs and 3 (3.3%) MEs were observed. These errors resulted when P/T Etest MICs were 1 doubling dilution apart from the BMD MICs. In conclusion, the new P/T Etest represents an accurate tool for performing antimicrobial susceptibility testing of , , and complex isolates with limited category errors.
哌拉西林他唑巴坦（P/T）是一种β-内酰胺类-β-内酰胺酶抑制剂合剂，常用于医院环境。Etest 是一种梯度扩散方法，是替代肉汤微量稀释（BMD）进行抗菌药物敏感性测试的一种方法。我们根据美国食品和药物管理局（FDA）和国际标准化组织（ISO）的标准 ISO 20776-2 标准，使用临床和实验室标准协会（CLSI）-FDA 和欧洲抗菌药物敏感性测试委员会（EUCAST）的解释性折点，对新的 P/T Etest 的性能进行了多中心评估，分别与 BMD 进行了比较。共测试了 977 株分离株（775 株、119 株和 83 株复杂分离株）。当分别遵循 FDA 和 ISO 20776-2 标准时，总体符合率（EA）分别为 96.4%和 96.6%。当同时遵循 FDA 和 ISO 标准时，EA 分别为 98.3%和 91.6%，对于复杂分离株。当同时应用 CLSI-FDA 和 ISO 标准时，分类符合率（CA）分别达到 93.0%、93.3%和 89.2%，对于 、和复杂分离株。在 中发现了 2 个非常大的错误（VME；1.1%）（2 株分离株）。没有发现其他重大错误（ME）或 VME。当应用 EUCAST 折点时，对于 和 ，CA 分别为 94.8%和 95.8%（目前尚无针对复杂分离株的折点）。在 中未观察到 VME，但发现了 2 个（0.4%）ME。在 分离株中，观察到 2 个（6.9%）VME 和 3 个（3.3%）ME。这些错误是由于 P/T Etest MIC 与 BMD MIC 相差 1 个稀释度引起的。总之，新的 P/T Etest 是一种准确的工具，可用于检测 、和复杂分离株的抗菌药物敏感性，分类错误有限。
