Chan K L, Levi K, Towner K J, Weston V C, Ramsay M M, Kean L H
Departments of Obstetrics and Gynaecology, City Hospital, Nottingham, UK.
J Obstet Gynaecol. 2006 Jul;26(5):402-6. doi: 10.1080/01443610600719925.
The objective of this study was to compare detection of group B streptococcal (GBS) carriage using 'real-time' polymerase chain reaction (PCR) and microbiological standard culture. The study design was a test accuracy study comparing a novel molecular technique against the standard microbiological cultural technique in normal pregnant women. The setting and population consisted of 143 pregnant women with pre-labour rupture of the membranes, recruited from two large teaching hospitals in the UK. The study examined the efficacy of a polymerase chain reaction (PCR) assay for screening pregnant women who presented with term rupture of the membranes. Low vaginal specimens were obtained from the women. The specimens were tested for GBS by conventional culture and with a GBS-specific real-time PCR assay. The main outcome measure was the sensitivity and specificity of the PCR assay with 95% confidence intervals (CI) compared with the standard culture. The length of time to obtain a result was also reported for both methods. Among the 143 women, the results of the culture were positive (at least one colony) for GBS in 20 women (14%). The PCR assay detected GBS carriage in 10 women (7%). As compared with the culture method, the sensitivity and specificity of the PCR assay were 45% and 99%, respectively. The positive and negative predictive values of the PCR assay were 90% and 92%, respectively. The length of time required to obtain results for the majority of women (94%) was <2.5 h for the PCR assay and at least 24 h for culture. While a rapid result (within 3 h) of carriage of GBS can be obtained by the PCR assay, at present, it cannot replace conventional culture without further optimisation of the DNA extraction method. The sensitivity may further be improved by testing both low vaginal and rectal specimens.
本研究的目的是比较使用“实时”聚合酶链反应（PCR）和微生物标准培养法检测B族链球菌（GBS）携带情况。研究设计为一项检测准确性研究，在正常孕妇中比较一种新型分子技术与标准微生物培养技术。研究地点和人群包括从英国两家大型教学医院招募的143例临产前胎膜破裂的孕妇。该研究检验了聚合酶链反应（PCR）检测法对胎膜足月破裂孕妇进行筛查的效果。从这些女性身上获取阴道下段标本。通过传统培养法和GBS特异性实时PCR检测法对标本进行GBS检测。主要结局指标是与标准培养法相比，PCR检测法的敏感性和特异性及其95%置信区间（CI）。还报告了两种方法获得结果所需的时间。在这143名女性中，20名女性（14%）的培养结果显示GBS呈阳性（至少有一个菌落）。PCR检测法检测出10名女性（7%）携带GBS。与培养法相比，PCR检测法 的敏感性和特异性分别为45%和99%。PCR检测法的阳性预测值和阴性预测值分别为90%和92%。对于大多数女性（94%），PCR检测法获得结果所需的时间<2.5小时，而培养法则至少需要24小时。虽然PCR检测法可以快速（3小时内）得出GBS携带情况的结果，但目前在DNA提取方法未进一步优化的情况下，它无法取代传统培养法。通过同时检测阴道下段和直肠标本，敏感性可能会进一步提高。
