Holzknecht B J, Hansen D S, Nielsen L, Kailow A, Jarløv J O
Department of Clinical Microbiology, Herlev and Gentofte Hospital, University of Copenhagen, Herlev, Denmark.
New Microbes New Infect. 2017 Jan 12;16:54-59. doi: 10.1016/j.nmni.2016.12.020. eCollection 2017 Mar.
Vancomycin-resistant enterococci (VRE) are increasingly important nosocomial pathogens and screening for colonization status is a mainstay in infection control. We implemented PCR-based screening during -positive outbreaks in four university hospitals in Copenhagen, Denmark. Xpert was performed directly on rectal swabs and the PCR result was used to guide infection control measures. Concurrently, all samples were selectively cultured including an overnight enrichment step. Diagnostic accuracy was calculated as well as turnaround time and the impact of the earlier available PCR results on infection control decision making. In all, 1110 samples were analysed. The PCR positivity rate was 13.8% and culture positivity rate was 15.2%. The diagnostic accuracy of the part of the assay was high with a sensitivity of 87.1%, a specificity of 99.7%, and positive and negative predictive values of 98.0% and 97.7%, respectively. The PCR had a considerably lower specificity of 77.6% and a positive predictive value of 0.4%. In 1067 (96.1%) samples, PCR results were reported within 1 day, whereas median culture turnaround time was 3 days. The saving of time to available results corresponded to 141 saved isolation days and 292 saved transmission risk days. False-negative or false-positive PCR results led to six additional transmission risk days and 13 additional isolation days, respectively. The PCR had high diagnostic accuracy and the prompt availability of results gave a considerable benefit for infection control decision making.
耐万古霉素肠球菌（VRE）是日益重要的医院病原体，对定植状态进行筛查是感染控制的主要手段。我们在丹麦哥本哈根的四家大学医院的阳性暴发期间实施了基于PCR的筛查。直接对直肠拭子进行Xpert检测，并将PCR结果用于指导感染控制措施。同时，对所有样本进行选择性培养，包括过夜富集步骤。计算诊断准确性以及周转时间，以及更早获得的PCR结果对感染控制决策的影响。总共分析了1110个样本。PCR阳性率为13.8%，培养阳性率为15.2%。该检测部分的诊断准确性较高，敏感性为87.1%，特异性为99.7%，阳性和阴性预测值分别为98.0%和97.7%。Xpert PCR的特异性相当低，为77.6%，阳性预测值为0.4%。在1067个（96.1%）样本中，PCR结果在1天内报告，而培养的中位周转时间为3天。获得结果节省的时间相当于节省了141个隔离日和292个传播风险日。PCR假阴性或假阳性结果分别导致额外6个传播风险日和13个隔离日。Xpert PCR具有较高的诊断准确性，结果的快速可得性对感染控制决策有很大益处。
