Medical Microbiology, General Hospital Sint-Jan AV Brugge-Oostende, Ruddershove 10, 8000 Brugge, Belgium.
Infection. 2010 Apr;38(2):98-101. doi: 10.1007/s15010-009-9117-0. Epub 2010 Feb 27.
As the prompt detection of methicillin-resistant Staphylococcus aureus (MRSA) carriers upon admission is fundamental in the MRSA prevention strategy of our hospital, the infection control team is eagerly seeking the most sensitive and rapid screening method. The aim of this study was to compare the performance of two molecular techniques with a conventional MRSA-selective culture test (Bio-Rad chromogenic MRSASelect) in order to elucidate the suitability of the assays specifically in an expected low MRSA prevalence population.
The anterior nares and throat of 500 patients and visitors attending the emergency department of Sint-Jan General Hospital between May and June 2007 were sampled, and MRSA carriage was determined by selective culture after enrichment and the BD GeneOhm StaphSR and the Cepheid Xpert MRSA assays.
Eight MRSA carriers were detected by selective culture (1.6% prevalence). The sensitivity, specificity, positive [corrected] predictive value, and negative [corrected] predictive value were 62.5, 99.0, 50.0, and 99.4% for BD GeneOhm StaphSR and 62.5, 97.7, 31.3, and 99.4% for Cepheid Xpert MRSA, respectively.
We conclude that MRSA rapid screening techniques must be interpreted cautiously in a low-prevalence population, as the sensitivity is lower than in selected high-risk populations. MRSA carriers detected with molecular techniques must be confirmed by conventional culture methods for follow-up. The specificity and negative predictive value indicate that molecular rapid methods are worthwhile to be considered in MRSA-preventive strategies.
由于及时发现耐甲氧西林金黄色葡萄球菌（MRSA）携带者对于我院的 MRSA 预防策略至关重要，感染控制团队正在急切寻求最敏感和快速的筛查方法。本研究旨在比较两种分子技术与传统的 MRSA 选择性培养试验（Bio-Rad 显色性 MRSASelect）的性能，以明确这些检测方法在预期 MRSA 低流行人群中的适用性。
2007 年 5 月至 6 月期间，对 Sint-Jan 综合医院急诊科的 500 名患者和访客的前鼻腔和咽喉进行了采样，通过选择性培养（富集后）和 BD GeneOhm StaphSR 与 Cepheid Xpert MRSA 检测来确定 MRSA 携带情况。
选择性培养检测出 8 例 MRSA 携带者（流行率为 1.6%）。BD GeneOhm StaphSR 的敏感性、特异性、阳性预测值和阴性预测值分别为 62.5%、99.0%、50.0%和 99.4%，Cepheid Xpert MRSA 的敏感性、特异性、阳性预测值和阴性预测值分别为 62.5%、97.7%、31.3%和 99.4%。
我们得出结论，在低流行人群中，MRSA 快速筛查技术的结果必须谨慎解读，因为其敏感性低于选定的高风险人群。通过分子技术检测到的 MRSA 携带者必须通过传统的培养方法进行确认，以进行后续跟踪。特异性和阴性预测值表明，分子快速方法值得在 MRSA 预防策略中加以考虑。
