Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
Department of Laboratory Medicine, Daping Hospital, Army Medical University, Chongqing, China.
Lett Appl Microbiol. 2020 Jan;70(1):42-47. doi: 10.1111/lam.13240. Epub 2019 Nov 29.
The increasing frequency of class A KPC enzymes, class B metallo-β-lactamases (MBLs) and class D OXA-48 enzymes in Enterobacteriaceae makes their early identification urgent. A simple commercial MASTDISCS combi Carba plus disc system (MAST-Carba plus) was designed for the identification of MBLs, KPC and OXA-48 carbapenemase genes in Enterobacteriaceae. To validate the MAST-Carba plus, a total of 77 isolates of carbapenemase-producing Enterobacteriaceae (CPE) and 84 isolates of noncarbapenemase-producing Enterobacteriaceae (non-CPE) were selected for differentiation of the genes of Enterobacteriaceae by MAST-Carba plus. Meanwhile, the carbapenemase genes such as bla , bla , bla , bla and bla were detected by PCR (polymerase chain reaction). Thus, when considered on the basis of PCR results, the sensitivity of MAST-Carba plus detection of KPC strains is 82·3%, the specificity is 100·0%, the positive predictive value is 100·0% and the negative predictive value is 92·4%. For MBLs strains, the sensitivity is 100·0%, the specificity is 97·1%, the positive predictive value is 84·6% and the negative predictive value is 100·0%. For OXA-48 strains, the sensitivity is 100·0%, the specificity is 99·4%, the positive predictive value is 80·0% and the negative predictive value is 100·0%. Our findings suggest that MAST-Carba plus is a rapid and promising method for identifying the MBLs, KPC and OXA-48 carbapenemase genes in Enterobacteriaceae, which could be exploited in basic microbiology laboratory to prevent the transmission of CPE. SIGNIFICANCE AND IMPACT OF THE STUDY: Not only detection of carbapenemases but also identification of their genes accurately and rapidly in Enterobacteriaceae is still a major challenge for clinical laboratories in order to prevent the transmission of carbapenemase-producing Enterobacteriaceae (CPE). Therefore, this study aimed to evaluate the performance of a new rapid method (MASTDISCS combi Carba plus) for the identification of metallo-β-lactamases (MBLs), KPC and OXA-48 carbapenemase genes in Enterobacteriaceae clinical isolates.
肠杆菌科中 A 类 KPC 酶、B 类金属β-内酰胺酶 (MBLs) 和 D 类 OXA-48 酶的频率不断增加，使得对其进行早期鉴定变得尤为紧迫。一种简单的商业 MASTDISCS combi Carba plus 圆盘系统 (MAST-Carba plus) 被设计用于鉴定肠杆菌科中的 MBLs、KPC 和 OXA-48 碳青霉烯酶基因。为了验证 MAST-Carba plus，我们选择了 77 株产碳青霉烯酶肠杆菌科（CPE）和 84 株非产碳青霉烯酶肠杆菌科（non-CPE）的分离株，通过 MAST-Carba plus 对肠杆菌科的基因进行区分。同时，通过聚合酶链反应（PCR）检测 bla、bla、bla、bla 和 bla 等碳青霉烯酶基因。因此，基于 PCR 结果，MAST-Carba plus 检测 KPC 株的灵敏度为 82.3%，特异性为 100.0%，阳性预测值为 100.0%，阴性预测值为 92.4%。对于 MBLs 株，灵敏度为 100.0%，特异性为 97.1%，阳性预测值为 84.6%，阴性预测值为 100.0%。对于 OXA-48 株，灵敏度为 100.0%，特异性为 99.4%，阳性预测值为 80.0%，阴性预测值为 100.0%。我们的研究结果表明，MAST-Carba plus 是一种快速、有前途的方法，可用于鉴定肠杆菌科中的 MBLs、KPC 和 OXA-48 碳青霉烯酶基因，这可以在基础微生物学实验室中得到利用，以防止 CPE 的传播。
临床实验室不仅要准确快速地检测碳青霉烯酶，还要准确快速地检测其基因，这仍然是肠杆菌科面临的主要挑战，目的是为了防止碳青霉烯酶产生肠杆菌科（CPE）的传播。因此，本研究旨在评估一种新的快速方法（MASTDISCS combi Carba plus）在鉴定肠杆菌科临床分离株中金属β-内酰胺酶（MBLs）、KPC 和 OXA-48 碳青霉烯酶基因的性能。
