晚孕期阴道B族链球菌定植与新生儿感染的关系

Relationship between group BStreptococcus colonization in late pregnancies and neonatal infection

目的：探讨孕妇妊娠晚期阴道B族链球菌（group BStreptococcus，GBS）的定植情况，及其对新生儿GBS感染的影响。方法2014年6月1日至2015年5月31日在厦门市妇幼保健院建立围产保健档案并分娩的17019例孕妇，于35～37孕周产前检查时或早产孕妇（无论孕周）在入院时取阴道下段1/3处分泌物进行GBS培养，其中1472例同时行实时荧光定量-聚合酶链反应（polymerase chain reaction，PCR）GBS DNA检测。GBS定植孕妇（GBS培养和/或PCR DNA阳性）在分娩发动或胎膜破裂时给予产时抗生素预防（intrapartum antibiotic prophylaxis，IAP）。比较2种检测方法GBS的检出率，并分析定植阳性及IAP对新生儿GBS感染的影响，以及新生儿早发型GBS疾病（early-onset GBS disease，GBS-EOD）的高危因素。采用两独立样本t检验、χ^2检验及Logistic回归分析进行统计学处理。结果GBS培养检出率为14.43%（2456/17019）， PCR DNA检出率为14.13%（288/1472），2种检测方法总体GBS定植率为14.52%（2472/17019）。以GBS培养为金标准，PCR DNA检测的敏感度、特异度、阳性预测值和阴性预测值分别为95.05%、98.74%、92.31%和99.21%。17019例孕妇分娩活产儿17332例，其中GBS-EOD 31例。阴道GBS定植孕妇新生儿GBS-EOD发生率为1.05%（26/2472），是无定植孕妇[0.34‰（5/14547）]的31倍。31例GBS-EOD患儿中GBS肺炎24例，GBS败血症5例，GBS脑膜炎2例；病死率为6.45%（2/31）。Logistic回归分析发现，孕妇绒毛膜羊膜炎是新生儿GBS-EOD的危险因素（OR=40.425，95%CI：7.514～379.782，P=0.000）。阴道GBS定植孕妇充分IAP者新生儿发生GBS-EOD的比例为0.94%（23/2443），明显低于未充分IAP者[10.34%（3/29）]（χ^2=24.350，P＜0.01）。结论孕妇妊娠晚期阴道GBS定植对新生儿有不良影响，IAP可以降低GBS定植孕妇新生儿感染率。故也许有必要对孕妇常规筛查GBS并对定植阳性者进行IAP。

ObjectiveTo study the effects of group BStreptococcus （GBS） colonization in late pregnancies on neonatal GBS infection.MethodsA total of 17 019 pregnant women who received antenatal care and delivered in Xiamen Maternal and Child Care Hospital from June 1, 2014 to May 31, 2015 were enrolled in this study. Secretions from the lower third of the vagina in the pregnant women at 35-37 weeks of gestation or having premature baby（regardless of gestational age） were obtained to test GBS by standard bacterial culture, and 1 472 cases underwent GBS DNA test by real-time fluorescent quantitative-polymerase chain reaction （PCR） meanwhile. The pregnant women colonized with GBS （GBS culture and/or PCR DNA test positive） were given intrapartum antibiotic prophylaxis （IAP） during parturition or rupture of fetal membranes. Detection rate of the two methods was compared, and the effects of GBS colonization and IAP on neonatal GBS infection were analyzed to identify the risk factors of neonatal early-onset GBS disease （GBS-EOD）. Two independent samplest-test,Chi-square test and Logistic regression analysis were used for statistical analysis. ResultsThe detection rate of GBS culture and PCR DNA test was 14.43% （2 456/17 019） and 14.13%（288/1 472）, respectively. The total colonization rate was 14.52%（2 472/17 019）. Based on the culture results as golden criteria, the sensitivity, specificity, positive predictive value and negative predictive value of PCR assay were 95.05%, 98.74%, 92.31% and 99.21%, respectively. There were 17 332 deliveries from the 17 019 pregnant women, of which 31 cases had GBS-EOD. The incidence of neonatal GBS-EOD in maternal GBS colonization [1.05%（26/2 472）] was 31 times higher than in pregnant women without GBS colonization [0.34‰（5/14 547）]. Among the 31 infants with GBS-EOD, 24 had pneumonia, five had sepsis, and two had meningitis. The case fatality rate was 6.45%（2/31）. Logistic regression analysis found that chorioamnionitis was an independent risk factor of neonatal GBS-EOD （OR=40.425, 95%CI： 7.514-379.782,P=0.000）. Compared with the non-IAP group,IAP group had a lower incidence of GBS-EOD among the pregnant women colonized with GBS [0.94%（23/2 443） vs 10.34%（3/29）,χ^2=24.350,P〈0.01].ConclusionsGBS colonization in late pregnant women has adverse effects. Therefore, routine maternal rectovaginal culture of GBS may be necessary and IAP should be applied in those with GBS colonization.