Zhang Sirui, Mi Peng, Wang Jingdan, Li Pu, Luo Kai, Liu Shuyan, Al-Shamiri Mona Mohamed, Lei Jin'e, Lai Simin, Han Bei, Chen Yanjiong, Han Lei, Han Shaoshan
Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, China.
Department of Laboratory Medicine, Shaanxi Provincial People's Hospital, Xi'an, China.
Front Microbiol. 2023 Jul 13;14:1185450. doi: 10.3389/fmicb.2023.1185450. eCollection 2023.
The modified carbapenem inactivation method (mCIM) recommended by the Clinical and Laboratory Standards Institute is not applicable for detecting carbapenemases in . Four currently reported phenotypic detection methods, namely, the modified Hodge test, the mCIM, the adjusted mCIM, and the simplified carbapenem inactivation method (sCIM), did not perform well in our 90 clinical isolates. Thus, the minimal inhibitory concentrations (MICs) of carbapenems and the existence and expression of carbapenemase-encoding genes were detected to explain the results. According to the E-test, which was more accurate than the VITEK 2 system, 80.0 and 41.1% were resistant to imipenem (IPM) and meropenem (MEM), respectively, and 14.4 and 53.3% exhibited intermediate resistance, respectively. Five β-lactamase genes were found, of which , , and were detected more frequently in 85 non-susceptible strains. The expression of was positively correlated with the MIC values of IPM and MEM. Therefore, an improved approach based on the mCIM, designated the optimized CIM (oCIM), was developed in this study to detect carbapenemases more accurately and reproducibly. The condition was improved by evaluating the factors of inoculum, incubation broth volume, and MEM disk incubation time. Obvious high sensitivity (92.94%) and specificity (100.00%) were obtained using the oCIM, which was cost-effective and reproducible in routine laboratory work.
临床和实验室标准协会推荐的改良碳青霉烯灭活方法（mCIM）不适用于检测……中的碳青霉烯酶。目前报道的四种表型检测方法，即改良 Hodge 试验、mCIM、调整后的 mCIM 和简化碳青霉烯灭活方法（sCIM），在我们的90株临床分离株中表现不佳。因此，检测了碳青霉烯类药物的最低抑菌浓度（MIC）以及碳青霉烯酶编码基因的存在和表达，以解释结果。根据比 VITEK 2系统更准确的 E-test，分别有80.0%和41.1%的菌株对亚胺培南（IPM）和美罗培南（MEM）耐药，分别有14.4%和53.3%表现出中介耐药。发现了5种β-内酰胺酶基因，其中……在85株非敏感菌株中检测频率更高。……的表达与IPM和MEM的MIC值呈正相关。因此，本研究开发了一种基于mCIM的改进方法，称为优化CIM（oCIM），以更准确、可重复地检测碳青霉烯酶。通过评估接种量、孵育肉汤体积和MEM纸片孵育时间等因素改进了条件。使用oCIM获得了明显较高的敏感性（92.94%）和特异性（100.00%），该方法在常规实验室工作中具有成本效益且可重复。
