Scholtz Sophie L, Faron Matthew L, Buchan Blake W, Ledeboer Nathan A
Medical College of Wisconsin, Milwaukee, WI, USA.
Wisconsin Diagnostic Laboratories, Milwaukee, WI, USA.
Am J Clin Pathol. 2022 May 4;157(5):781-788. doi: 10.1093/ajcp/aqab195.
Aerococcus spp are Gram-positive cocci increasingly recognized as uropathogens. The Clinical and Laboratory Standards Institute recently published specific breakpoints for Aerococcus spp (M45, third edition); however, the standardized method used for antimicrobial susceptibility testing (AST) requires media not often maintained in clinical laboratories. The purpose of this study was to evaluate and compare alternative methods of AST for Aerococcus isolates.
AST was performed on 134 clinical isolates using the Etest on three different types of agar, Vitek 2, and BD Phoenix. These results were compared with broth microdilution using the Sensititre STP6F.
Aerococcus exhibited low minimum inhibitory concentrations to benzylpenicillin, meropenem, linezolid, and vancomycin. Variable resistance was seen to levofloxacin, ceftriaxone, and tetracycline. Meropenem and vancomycin met all acceptance criteria with every alternative method tested. Benzylpenicillin and linezolid did not meet essential agreement on any AST method. Tetracycline met the majority of acceptance criteria with the exception of more than 3% very major error when using the Etest on chocolate agar, the Vitek 2, and BD Phoenix.
Overall, the alternate AST method with the highest agreement with broth microdilution was the Etest on Mueller-Hinton agar with 5% sheep blood and may be an optimal alternative to broth microdilution.
气球菌属是革兰氏阳性球菌，越来越多地被认为是尿路病原体。临床和实验室标准协会最近公布了气球菌属的特定断点（M45，第三版）；然而，用于抗菌药物敏感性试验（AST）的标准化方法需要临床实验室不常保存的培养基。本研究的目的是评估和比较气球菌分离株AST的替代方法。
使用Etest在三种不同类型的琼脂、Vitek 2和BD Phoenix上对134株临床分离株进行AST。将这些结果与使用Sensititre STP6F的肉汤微量稀释法进行比较。
气球菌对苄青霉素、美罗培南、利奈唑胺和万古霉素表现出低最低抑菌浓度。对左氧氟沙星、头孢曲松和四环素可见可变耐药性。美罗培南和万古霉素在所有测试的替代方法中均符合所有接受标准。苄青霉素和利奈唑胺在任何AST方法上均未达到基本一致性。四环素符合大多数接受标准，但在巧克力琼脂上使用Etest、Vitek 2和BD Phoenix时，非常重大误差超过3%。
总体而言，与肉汤微量稀释法一致性最高的替代AST方法是在含5%羊血的Mueller-Hinton琼脂上进行Etest，可能是肉汤微量稀释法的最佳替代方法。
