快速筛查耐甲氧西林金黄色葡萄球菌（MRSA）对识别和更早隔离 MRSA 阳性患者的影响。
The effect of rapid screening for methicillin-resistant Staphylococcus aureus (MRSA) on the identification and earlier isolation of MRSA-positive patients.
机构信息
Department of Clinical Microbiology, Education and Research Centre, Royal College of Surgeons, Ireland.
出版信息
Infect Control Hosp Epidemiol. 2010 Apr;31(4):374-81. doi: 10.1086/651093.
OBJECTIVES
(1) To determine whether rapid screening with polymerase chain reaction (PCR) assays leads to the earlier isolation of patients at risk for methicillin-resistant Staphylococcus aureus (MRSA) colonization, (2) to assess compliance with routine MRSA screening protocols, (3) to confirm the diagnostic accuracy of the Xpert MRSA real-time PCR assay (Cepheid) by comparison with culture, and (4) to compare turnaround times for PCR assay results with those for culture results.
DESIGN
Before-and-after study conducted in a 700-bed acute tertiary care referral hospital. Study periods were (1) a 5-week period before PCR testing began, (2) a 10-week period when the PCR assay was used, and (3) a 5-week period after PCR testing was discontinued.
RESULTS
Among 489 at-risk patients, MRSA was isolated from 20 (33%) of 60 patients during period 1, 77 (22%) of 349 patients during period 2, and 18 (23%) of 80 patients during period 3. Twenty-two (27%) of 82 at-risk patients were not screened during period 1, compared with 40 (10%) of 389 at-risk patients not screened during period 2 (P < .001). More MRSA-positive patients were preemptively isolated during periods 1 and 3 compared with period 2 (34 [24%] of 140 vs 28 [8%] of 389; P < .001); however, more MRSA-positive patients were isolated after notification of MRSA-positive results during period 2 (47 [13%] of 349) compared with periods 1 and 3 (2 [1%] of 140; P < .001). The sensitivity, specificity, positive predictive value, and negative predictive value of the PCR assay were 95%, 97%, 82%, and 99%, respectively. The mean turnaround time from receipt of specimens in the laboratory to PCR assay result was 2.6 hours.
CONCLUSIONS
Rapid screening with the Xpert MRSA PCR assay facilitated compliance with screening policies and the earlier isolation of MRSA-positive patients. Discrepant results confirm that PCR testing should be used as a screening tool rather than as a diagnostic tool.
目的
（1）确定聚合酶链反应（PCR）快速筛查是否能更早地隔离耐甲氧西林金黄色葡萄球菌（MRSA）定植的高危患者，（2）评估常规 MRSA 筛查方案的依从性，（3）通过与培养比较，确认 Xpert MRSA 实时 PCR 检测（Cepheid）的诊断准确性，（4）比较 PCR 检测结果与培养结果的周转时间。
设计
在一家拥有 700 张床位的急性三级转诊医院进行的前后对照研究。研究期间为（1）PCR 检测开始前的 5 周，（2）PCR 检测使用的 10 周，（3）PCR 检测停止后的 5 周。
结果
在 489 名高危患者中，第 1 期从 60 名患者中的 20 名（33%）分离出 MRSA，第 2 期从 349 名患者中的 77 名（22%），第 3 期从 80 名患者中的 18 名（23%）。第 1 期有 22 名（27%）高危患者未接受筛查，而第 2 期有 389 名高危患者中未接受筛查的有 40 名（10%）（P<.001）。与第 2 期相比，第 1 期和第 3 期有更多的 MRSA 阳性患者被预先隔离（34 [24%] 例 140 例 vs. 28 [8%] 例 389 例；P<.001）；然而，第 2 期报告 MRSA 阳性结果后，有更多的 MRSA 阳性患者被隔离（47 [13%] 例 349 例 vs. 第 1 期和第 3 期的 2 [1%] 例 140 例；P<.001）。PCR 检测的灵敏度、特异性、阳性预测值和阴性预测值分别为 95%、97%、82%和 99%。从实验室收到标本到 PCR 检测结果的平均周转时间为 2.6 小时。
结论
使用 Xpert MRSA PCR 快速筛查有助于遵守筛查政策，并更早地隔离 MRSA 阳性患者。不一致的结果证实，PCR 检测应作为筛查工具而不是诊断工具。
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