目的 探讨妊娠晚期孕妇B族链球菌带菌状况的检测方法及带菌对妊娠结局的影响.方法收集2008年12月-2009年6月在北京大学第一医院妇产科进行B族链球菌检测的孕妇617例,平均年龄为30.1岁,其中高龄孕妇(≥35岁)80例;经产妇41例,初产妇576例;对617例孕妇于孕35～37周取阴道下1/3分泌物及肛周分泌物,应用细菌培养及实时PCR两种方法进行B族链球菌检测,并观察其妊娠结局.结果 (1)B族链球菌阳性检出率:B族链球菌培养阳性21例(3.4%,21/617),实时PCR检测阳性57例(9.2%,57/617).21例B族链球菌培养阳性孕妇,实时PCR检测均为阳性;36例实时PCR检测B族链球菌阳性、而细菌培养阴性孕妇在进行扩增测序后证实,34例为B族链球菌阳性,2例阴性.(2)实时PCR检测B族链球菌的诊断价值:实时PCR检测B族链球菌的敏感度为100%(55/55),特异度为99.6%(560/562).(3)B族链球菌阳性的相关因素:B族链球菌阳性孕妇平均年龄为(30.4±3.6)岁,阴性孕妇平均年龄为(30.9±3.5)岁,两者年龄比较,差异无统计学意义(P>0.05).经产妇B族链球菌阳性率为7.3%(3/41),初产妇阳性率为9.4%(54/576),两者比较,差异无统计学意义(P>0.05).高龄孕妇(≥35岁)B族链球菌阳性率高于年龄<35岁孕妇的阳性率,但差异无统计学意义(P>0.05).流产≥3次孕妇的B族链球菌阳性率与流产<3次孕妇比较,差异也无统计学意义(P>0.05).(4)分娩方式:B族链球菌阳性孕妇的剖宫产率为54.4%(31/57),阴性孕妇的剖宫产率为44.6%(250/560),两者比较,差异无统计学意义(P>0.05).(5)产时情况:B族链球菌阳性孕妇的胎膜早破发生率为33.3%(19/57),阴性孕妇的胎膜早破发生率为25.0%(140/560),两者比较,差异无统计学意义(P>0.05).B族链球菌阳性孕妇的宫内感染发生率为15.8%(9/57),显著高于阴性孕妇宫内感染发生率[6.6%(37/560)],两者比较,差异有统计学意义(P<0.05).B族链球菌阳性孕妇产后出血发生率和胎儿窘迫发生率均显著高于阴性孕妇(P<0.05),而早产发生率、羊水污染发生率在B族链球菌阳性与阴性孕妇中比较,差异无统计学意义(P>0.05).(6)新生儿感染率:B族链球菌阳性孕妇所分娩的新生儿中,新生儿感染发生率为29.8%(17/57);阴性孕妇所分娩的新生儿中,新生儿感染率为13.2%(77/560),两者比较,差异有统计学意义(P<0.05).B族链球菌带菌孕妇的新生儿中,有1例发生了严重早发感染,经及时处理,结局良好.结论 妊娠晚期孕妇B族链球菌携带明显增加宫内感染及新生儿感染的发生率,对妊娠结局造成不良影响.实时PCR检测B族链球菌感染有较高的敏感度和特异度,有望成为妊娠晚期孕妇常规检测B族链球菌的一种方法.%Objective To study the sensitivity of the real-time polymerase chain reaction (RT-PCR) in detecting group B streptococcus (GBS) in late pregnant women and the influence of vaginal/rectal GBS colonization on maternal and neonatal outcomes. Methods Microbiological culture and RT-PCR for GBS were both performed for each sample taken from the vagina and rectus in 617 gravidas at 35-37 weeks of gestation, with an average age of 30.1, among which 80 aged over 35. Forty-one out of the 617 women were multiparous and 576 primiparous. The laboratory results were collected and the pregnant outcomes were followed. Results (1) Out of the 617 gravidas, 21 (3.4%) were GBS positive by culture (all positive in RT-PCR) and 57 (9.2%) were GBS positive by RT-PCR. Thirth-six cases with PCR positive but culture negative results were analyzed by sequencing, and 34 showed GBS positive and 2 negative. (2) The sensitivity and specificity of RT-PCR was 100% (55/55) and 99.6% (560/562) respectively. (3) The average age of GBS positive gravidas was 30 ± 4, without significant difference compared with that of GBS negative women (31±4), P>0.05. The GBS positive rates were also similar between the primiparas and the muliparous [7.3% (3/41) vs.9.4% (54/576)] , between elderly women and those under the age of 35, and between those women who had abortions over and less than 3 times (all P>0.05). (4) No significant difference was found in the cesarean section rate between the GBS postitive and negative group [54.4% (31/57) vs.44. 6% (250/560), P>0.05]. (5) Compared with the GBS negative group, the GBS positive group had higher incidence of intrauterine infection [6.6% (37/560) vs. 15.8% (9/57)], postpartum hemorrhage (2.9% vs.10.5%) and fetal distress (25.9% vs. 38.6% ) all P <0.05, but had similar incidence of premature rupture of membranes [25.0% (140/560) vs. 33.3% (19/57) ], pretcrm birth and meconium-stained amniotic fluid. (6) The neonatal infection rate in the GBS positive group was significantly higher than that of the GBS negative group [29.8% (17/57) vs. 13.2% (77/560), P < 0.05]. One neonate in the GBS positive group developed early-onset severe GBS infection and achieved better outcome under proper treatment. Conclusions Maternal GBS carrier at 35-37 weeks of gestation can lead to adverse pregnant outcomes by increasing the incidences of intrauterine infection and neonatal infections. However, RT-PCR could be a routine method to detect GBS status in late pregnant women with its higher sensitivity and specificity.
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