a Laboratoire de Microbiologie clinique , Groupe Hospitalier Paris Saint-Joseph , Paris , France ;
b Service des Urgences , Groupe Hospitalier Paris Saint-Joseph , Paris , France.
Infect Dis (Lond). 2016 Sep;48(9):695-8. doi: 10.1080/23744235.2016.1186831. Epub 2016 May 26.
The β LACTA™ test (BLT) is a chromogenic test detecting resistance to third-generation cephalosporins on bacterial colonies. Some studies have shown that this test can be used directly in urine samples. The aim of this study was to determine the optimal conditions of use of this test in order to detect the ESBL-producing bacteria directly in urine samples. During a 4-months period, a total of 365 consecutive urine samples were tested with the BLT using the recommendation of the manufacturer. We isolated 56 ESBL-producing bacteria and 17 AmpC-overproducing bacteria. ESBL- and/or AmpC β-lactamase-producing bacteria isolates were systematically characterized by disc diffusion antibiotic susceptibility testing interpreted according to the guidelines of EUCAST. The sensitivity and the specificity for 3GC-resistance detection, regardless the mechanism of resistance, were, respectively, 60.3% and 100%, whereas for ESBL detection, it was, respectively, 75.4% and 99.7%. We applied then modification of the initial protocol considering urines with a bacteriuria >1000/μL, a reading time at 30 min and considering any change of the initial colour as positive. The overall sensitivity was 81% and the sensitivity for ESBL-detection raised to 95.7%.
β LACTA™ 测试（BLT）是一种检测细菌菌落对第三代头孢菌素耐药性的显色测试。一些研究表明，该测试可直接用于尿液样本。本研究旨在确定该测试在尿液样本中直接检测产 ESBL 细菌的最佳使用条件。在 4 个月的时间里，我们使用制造商的建议对总共 365 份连续的尿液样本进行了 BLT 测试。我们分离出 56 株产 ESBL 细菌和 17 株高产 AmpC 酶细菌。通过纸片扩散抗生素药敏试验对 ESBL 和/或 AmpC β-内酰胺酶产生菌进行系统鉴定，结果根据 EUCAST 指南进行解释。无论耐药机制如何，该测试对 3GC 耐药性检测的灵敏度和特异性分别为 60.3%和 100%，而对 ESBL 检测的灵敏度和特异性分别为 75.4%和 99.7%。然后，我们根据初始方案进行了修改，考虑到尿液中细菌计数>1000/μL、30 分钟读数时间以及将任何初始颜色变化视为阳性。总的灵敏度为 81%，ESBL 检测的灵敏度提高到 95.7%。
