Carbapenemase-producing Enterobacterales (CPE) have become a global health concern. Current molecular detection methods require special equipment and reagents. Thus, there is an urgent need for a highly sensitive, specific, and simple method for phenotypic detection of CPE in clinical microbiology laboratories. A simplified carbapenem inactivation method (sCIM) was recently reported. However, its utility for CPE detection has not been sufficiently evaluated to date. We evaluated the sCIM and compared it with the modified CIM (mCIM), using 133 CPE strains (producing IMP, 92; NDM, 11; NDM and OXA-48–like, 1; KPC, 13; OXA-48–like, 12; GES-24, 3; Nmc-A, 1) and 82 non-CPE strains (extended spectrum β-lactamase, 61; AmpC, 21). The sCIM was conducted by loading bacteria onto imipenem and meropenem disks. When imipenem disks with a 1+ bacterial load were used, the sensitivity and specificity of the sCIM were 97.0% and 100%, and those of the mCIM were 97.0% and 96.3%, respectively. The specificity of the sCIM decreased to 57.3% when the bacterial load on imipenem disks was increased to 2+. In contrast, when meropenem disks with a 1+ bacterial load were used, the sCIM had a lower sensitivity (78.2%) and an equivalent specificity (100%). When meropenem disks with a bacterial load of 2+ were used, the sensitivity and specificity of the sCIM increased to 96.2% and 93.9%, respectively. The diameter of the inhibition zone on meropenem disks was larger than that on imipenem disks, and the sCIM was less sensitive when meropenem disks were used. In addition, sCIM detection rates when using meropenem disks were particularly low for OXA-48–like producers (bacterial load 1+, 0/12; bacterial load 2+, 10/12). Our results indicate that the sensitivity and specificity of the sCIM was dependent on the bacterial load and that large bacterial loads led to false positives for AmpC and extended spectrum β-lactamase producers. Thus, the sCIM has high sensitivity and specificity for appropriate bacterial loads when imipenem disks are used.

产碳青霉烯酶的肠杆菌(CPE) 已成为全球关注的健康问题。目前的分子检测方法需要特殊的设备和试剂。因此，迫切需要一种高度灵敏、特异且简单的方法用于临床微生物学中 CPE 的表型检测。实验室。最近报道了一种简化的碳青霉烯灭活方法 (sCIM)。然而，迄今为止，尚未充分评估其在 CPE 检测中的效用。我们使用 133 个 CPE 菌株（产生 IMP，92；NDM，11；NDM 和 OXA-48 样，1；KPC，13；OXA-48 样，12 ；GES-24, 3；Nmc-A, 1) 和 82 个非 CPE 菌株（超广谱 β-内酰胺酶，61；AmpC，21）。sCIM 是通过将细菌加载到亚胺培南和美罗培南盘上来进行的。当亚胺培南磁盘带有 1+sCIM 的敏感性和特异性分别为 97.0% 和 100%，mCIM 的敏感性和特异性分别为 97.0% 和 96.3%。当亚胺培南圆盘上的细菌负荷增加到 2+ 时，sCIM 的特异性降低到 57.3%。相比之下，当使用细菌负荷为 1+ 的美罗培南圆片时，sCIM 具有较低的灵敏度 (78.2%) 和等效的特异性 (100%)。当使用细菌载量为 2+ 的美罗培南圆片时，sCIM 的敏感性和特异性分别增加到 96.2% 和 93.9%。直径美罗培南片上的抑菌圈大于亚胺培南片，使用美罗培南片时sCIM敏感性较低。此外，对于 OXA-48 样生产者（细菌载量 1+，0/12；细菌载量 2+，10/12），使用美罗培南磁盘时的 sCIM 检测率特别低。我们的结果表明 sCIM 的敏感性和特异性取决于细菌负荷，并且大量细菌负荷导致 AmpC 和超广谱 β-内酰胺酶生产者的假阳性。因此，当使用亚胺培南圆片时，sCIM 对适当的细菌负荷具有高灵敏度和特异性。