Isfahan Endocrine and Metabolism Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
Department of Laboratory Medicine, Amin Hospital, Isfahan University of Medical Sciences, Isfahan, Iran.
Microbiol Spectr. 2024 Jul 2;12(7):e0038624. doi: 10.1128/spectrum.00386-24. Epub 2024 Jun 4.
Rapid detection of carbapenemase-producing Enterobacteriaceae (CPE) is urgently needed to prevent their spread in healthcare settings. Here, we have evaluated the performance of the phenotypic methods for detection of carbapenemase production directly from bacterial cultures. A total of 99 clinical and rectal Enterobacteriaceae isolates were included (81 carrying known carbapenemase-encoding genes and 18 without carbapenemase production). All isolates were subjected to the five phenotypic tests including in-house Carba NP (iCarba NP), modified-Carba NP, E-Test MBL, modified Hodge test (MHT), and commercial combination disk test. Test results were read at different time points for iCarba NP and modified-Carba (1 min, 5 min, 15 min, 1 h and 2 h). The sensitivity and specificity of the iCarba NP were 78.87% and 100%, respectively, whereas those of the modified-Carba NP test were 95.06% and 94.44%, respectively. False-negative results were detected in four OXA-48 isolates with the use of modified-Carba NP, whereas one non-carbapenemase isolate had false-positive results. The sensitivity/specificity was 91.30%/100% and 80.25%/83.33% for the E-Test MBL and MHT, respectively. The sensitivity and specificity of the aminophenylboronic acid synergy test were 100% and 97.94%, respectively, whereas those of the dipicolinic acid synergy test were 82.61% and 96.23%, respectively. Rapid, simple, and reliable methods are needed for laboratory detection of CPE isolates to improve the detection and surveillance of these clinically relevant pathogens in an epidemiological context. We conclude that the modified-Carba NP test can be one of the reliable tests for the prediction of carbapenemase-producing bacteria.IMPORTANCEThe emergence of carbapenem resistance among Gram-negative bacteria is a serious global health threat. Here, we investigate the performance of the five phenotypic assays against carbapenemase-producing and carbapenemase-non-producing Enterobacteriaceae. Accurate and rapid detection of CPE isolates is critically required for clinical management and treatment of infections caused by these organisms. Among the five evaluated phenotypic tests, the mCNP test presented the highest sensitivity (95.06%) and, therefore, can be considered the best test to be used as a screening phenotypic methodology.
迫切需要快速检测产碳青霉烯酶肠杆菌科（CPE），以防止其在医疗机构中传播。在此，我们评估了直接从细菌培养物中检测产碳青霉烯酶的表型方法的性能。共纳入 99 株临床和直肠肠杆菌科分离株（81 株携带已知的碳青霉烯酶编码基因，18 株无碳青霉烯酶产生）。所有分离株均接受五种表型检测，包括内部 Carba NP（iCarba NP）、改良 Carba NP、E-Test MBL、改良 Hodge 试验（MHT）和商业组合磁盘试验。iCarba NP 和改良 Carba NP（1 分钟、5 分钟、15 分钟、1 小时和 2 小时）的测试结果在不同时间点读取。iCarba NP 的灵敏度和特异性分别为 78.87%和 100%，而改良 Carba NP 试验的灵敏度和特异性分别为 95.06%和 94.44%。改良 Carba NP 检测到 4 株 OXA-48 分离株出现假阴性结果，而非产碳青霉烯酶分离株出现 1 株假阳性结果。E-Test MBL 和 MHT 的灵敏度/特异性分别为 91.30%/100%和 80.25%/83.33%。氨基苯硼酸协同试验的灵敏度和特异性分别为 100%和 97.94%，而二吡啶酸协同试验的灵敏度和特异性分别为 82.61%和 96.23%。需要快速、简单和可靠的方法来检测实验室中的 CPE 分离株，以提高在流行病学背景下对这些具有临床相关性的病原体的检测和监测。我们得出结论，改良的 Carba NP 试验可以作为预测产碳青霉烯酶细菌的可靠试验之一。
重要性：革兰氏阴性菌中碳青霉烯类耐药的出现是一个严重的全球健康威胁。在此，我们研究了五种表型检测方法对产碳青霉烯酶和非产碳青霉烯酶肠杆菌科的检测性能。准确快速检测 CPE 分离株对于临床管理和治疗这些生物体引起的感染至关重要。在评估的五种表型试验中，mCNP 试验的灵敏度最高（95.06%），因此可以被认为是作为筛选表型方法学的最佳试验。
