Extended-spectrum β-lactamase (ESBL)-producing Gram-negative bacteria (GNB) are increasingly identified as the cause of both community and healthcare-associated urinary tract infections (UTIs), with CTX-Ms being the most common ESBLs identified. CTX-M-producing GNB are resistant to most β-lactam antibiotics and are frequently multidrug–resistant, which limits treatment options. Rapid diagnostic tests that can detect ESBL-producing GNB, particularly CTX-M producers, in the urine of patients with UTIs are needed. Results from such a test could direct the selection of appropriate antimicrobial therapy at the point-of-care (POC). In this study, we show that a chromogenic, dual enzyme-mediated amplification system (termed DETECT [dual-enzyme trigger-enabled cascade technology]) can identify CTX-M-producing GNB from unprocessed urine samples in 30 minutes. We first tested DETECT against a diverse set of recombinant β-lactamases and β-lactamase-producing clinical isolates to elucidate its selectivity. We then tested DETECT with 472 prospectively collected clinical urine samples submitted for urine culture to a hospital clinical microbiology laboratory. Of these, 118 (25%) were consistent with UTI, 13 (11%) of which contained ESBL-producing GNB. We compared DETECT results in urine against a standard phenotypic method to detect ESBLs, and polymerase chain reaction and sequencing for CTX-M genes. DETECT demonstrated 90.9% sensitivity and 97.6% specificity (AUC, 0.937; 95% confidence interval, 0.822–1.000), correctly identifying 10 of 11 urine samples containing a clinically significant concentration of CTX-M-producing GNB (including Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis). Our results demonstrate the clinical potential of DETECT to deliver diagnostic information at the POC, which could improve initial antibiotic selection.

中文翻译：

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基于双酶的生化测试可快速检测临床尿液样本中产生第三代抗头孢菌素 CTX-M 的尿路病原体

产生超广谱 β-内酰胺酶 (ESBL) 的革兰氏阴性菌 (GNB) 越来越多地被确定为社区和医疗保健相关尿路感染 (UTI) 的原因，其中 CTX-Ms 是最常见的 ESBLs。产生 CTX-M 的 GNB 对大多数 β-内酰胺类抗生素具有耐药性，并且经常具有多重耐药性，这限制了治疗选择。需要能够检测尿路感染患者尿液中产生 ESBL 的 GNB，尤其是 CTX-M 产生者的快速诊断测试。这种测试的结果可以指导在护理点 (POC) 选择适当的抗菌治疗。在这项研究中，我们证明了一种显色剂，双酶介导的扩增系统（称为 DETECT [双酶触发级联技术]）可以在 30 分钟内从未处理的尿液样本中鉴定出产生 CTX-M 的 GNB。我们首先针对多种重组β-内酰胺酶和产生β-内酰胺酶的临床分离株测试了DETECT，以阐明其选择性。然后，我们用 472 个前瞻性收集的临床尿液样本测试了 DETECT，这些样本提交给医院临床微生物学实验室进行尿液培养。其中，118 个（25%）与 UTI 一致，其中 13 个（11%）含有产 ESBL 的 GNB。我们将尿液中的 DETECT 结果与检测 ESBL 的标准表型方法以及 CTX-M 基因的聚合酶链反应和测序进行了比较。DETECT 表现出 90.9% 的敏感性和 97.6% 的特异性（AUC，0.937；95% 置信区间，0.822–1.000），大肠杆菌、肺炎克雷伯菌和奇异变形杆菌）。我们的结果证明了 DETECT 在 POC 提供诊断信息的临床潜力，这可以改善初始抗生素选择。