Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut, USA.
Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
J Clin Microbiol. 2024 Jun 12;62(6):e0152023. doi: 10.1128/jcm.01520-23. Epub 2024 May 7.
There are increasing reports of carbapenem-resistant Enterobacterales (CRE) that test as cefepime-susceptible (S) or susceptible-dose dependent (SDD). However, there are no data to compare the cefepime testing performance of BD Phoenix automated susceptibility system (BD Phoenix) and disk diffusion (DD) relative to reference broth microdilution (BMD) against carbapenemase-producing (CP-CRE) and non-producing (non-CP CRE) isolates. Cefepime susceptibility results were interpreted according to CLSI M100Ed32. Essential agreement (EA), categorical agreement (CA), minor errors (miEs), major errors (MEs), and very major errors (VMEs) were calculated for BD Phoenix (NMIC-306 Gram-negative panel) and DD relative to BMD. Correlates were also analyzed by the error rate-bounded method. EA and CA for CP-CRE isolates ( = 64) were <90% with BD Phoenix while among non-CP CRE isolates ( = 58), EA and CA were 96.6%, and 79.3%, respectively. CA was <90% with DD for both cohorts. No ME or VME was observed for either isolate cohort; however, miEs were >10% for CP-CRE and non-CP CRE with BD Phoenix and DD tests. For error rate-bounded method, miEs were <40% for I + 1 to I - 1 ranges for CP-CRE and non-CP CRE with BD Phoenix. Regarding disk diffusion, miEs were unacceptable for all MIC ranges among CP-CRE. For non-CP CRE isolates, only I + 1 to I - 1 range was acceptable at 37.2%. Using this challenge set of genotypic-phenotypic discordant CRE, the BD Phoenix MICs and DD susceptibility results trended higher (toward SDD and resistant phenotypes) relative to reference BMD results yielding lower CA. These results were more prominent among CP-CRE than non-CP CRE.
越来越多的报告表明，碳青霉烯类耐药肠杆菌科（CRE）对头孢吡肟表现为敏感（S）或敏感剂量依赖性（SDD）。然而，目前尚无数据比较产碳青霉烯酶（CP-CRE）和非产碳青霉烯酶（non-CP CRE）分离株的 BD Phoenix 自动化药敏系统（BD Phoenix）和纸片扩散法（DD）与参考肉汤微量稀释法（BMD）检测头孢吡肟的性能。头孢吡肟药敏结果按照 CLSI M100Ed32 进行解释。计算了 BD Phoenix（NMIC-306 革兰氏阴性药敏板）和 DD 与 BMD 相比的主要一致率（EA）、分类一致率（CA）、小错误（miE）、大错误（ME）和非常大错误（VME）。还通过误差率限制法分析了相关性。CP-CRE 分离株（n=64）的 EA 和 CA 低于 90%，而非 CP CRE 分离株（n=58）的 EA 和 CA 分别为 96.6%和 79.3%。对于这两组分离株，DD 的 CA 均低于 90%。对于这两组分离株，均未观察到 ME 或 VME，但 BD Phoenix 和 DD 检测时 CP-CRE 和非 CP CRE 的 miE 均>10%。对于误差率限制法，BD Phoenix 检测 CP-CRE 和非 CP CRE 的 I+1 到 I-1 范围内的 miE<40%。关于纸片扩散法，对于 CP-CRE，所有 MIC 范围内的 miE 均不可接受。对于非 CP CRE 分离株，仅在 37.2°C 时 I+1 到 I-1 范围内的 miE 可接受。使用这种具有基因型-表型不一致的 CRE 的挑战集，BD Phoenix MIC 和 DD 药敏结果与参考 BMD 结果相比呈上升趋势（向 SDD 和耐药表型），导致 CA 降低。CP-CRE 中的这些结果比非 CP CRE 更显著。
