Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
Department of Laboratory Medicine and Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, 610072, China.
J Appl Microbiol. 2024 Aug 5;135(8). doi: 10.1093/jambio/lxae197.
Adequately and accurately identifying carbapenemase-producing Enterobacterales (CPE) is vital for selecting appropriate antimicrobial therapy and implementing effective infection control measures. This study aims to optimize the phenotypic detection method of carbapenemase for routine diagnostics in clinical microbiology laboratories.
Carbapenemase genes in 2665 non-duplicate CRE clinical strains collected from various regions of China were confirmed through whole-genome sequencing (WGS). The carbapenemase inhibition test (CIT) was conducted and interpreted using different methods and breakpoints, then compared with the NG-Test CARBA 5 for carbapenemase detection. The diagnostic performance of the CIT method was optimal when the carbapenemase types were determined by comparing the inhibition zone diameters of the imipenem disc with 3-aminophenylboronic acid (APB) plus ethylenediaminetetraacetic acid (EDTA) to those of the imipenem disc with either APB or EDTA alone, with a breakpoint of 4 mm. The overall sensitivities of the current CIT, the modified CIT, and NG-Test CARBA 5 were 91.4%, 94.9%, and 99.9%, respectively. For detecting isolates co-producing Klebsiella pneumoniae carbapenemase (KPC) and metallo-β-lactamases (MBLs), the modified CIT method had higher sensitivity than the current method (70.0% vs. 53.3%), though this difference was not statistically significant (P = 0.063). The NG-Test CARBA 5 showed excellent performance for multi-carbapenemases diagnosis, with sensitivity and specificity of 97.1% and 100%, respectively.
Optimizing and standardizing the CIT method for clinical use is necessary. It has certain advantages in diagnosing multi-carbapenemase and rare carbapenemase production. However, for identifying common carbapenemase types, the NG-Test CARBA 5 demonstrated superior performance.
准确鉴定产碳青霉烯酶肠杆菌科细菌（CPE）对于选择适当的抗菌治疗和实施有效的感染控制措施至关重要。本研究旨在优化临床微生物学实验室中用于常规诊断的碳青霉烯酶表型检测方法。
通过全基因组测序（WGS）确定了来自中国不同地区的 2665 株非重复 CRE 临床菌株中的碳青霉烯酶基因。采用不同方法和临界点进行碳青霉烯酶抑制试验（CIT），并与 NG-Test CARBA 5 进行比较，用于检测碳青霉烯酶。当通过比较含 3-氨基苯硼酸（APB）和乙二胺四乙酸（EDTA）的亚胺培南纸片与单独含 APB 或 EDTA 的亚胺培南纸片的抑菌圈直径来确定碳青霉烯酶类型时，CIT 方法的诊断性能最佳，临界点为 4 mm。目前的 CIT、改良的 CIT 和 NG-Test CARBA 5 的总灵敏度分别为 91.4%、94.9%和 99.9%。对于同时产肺炎克雷伯菌碳青霉烯酶（KPC）和金属β-内酰胺酶（MBLs）的分离株，改良的 CIT 方法比现行方法具有更高的灵敏度（70.0% vs. 53.3%），尽管差异无统计学意义（P = 0.063）。NG-Test CARBA 5 对多碳青霉烯酶诊断具有出色的性能，灵敏度和特异性分别为 97.1%和 100%。
有必要优化和标准化临床应用的 CIT 方法。它在诊断多碳青霉烯酶和罕见碳青霉烯酶产生方面具有一定优势。然而，对于常见碳青霉烯酶类型的鉴定，NG-Test CARBA 5 表现出优越的性能。
