To explore the risk factors of GBS infection during pregnancy.

Participants were pregnant women in late pregnancy (n=11 248) who were selected from Department of Obstetrics and Gynecology, Peking University International Hospital from January 2017 to August 2021. All of them underwent screening for GBS infection, 4 479 of them used vaginal swab test (single-swab culture group) , 1 239 used vaginal and rectal swabs tests (double-swab culture group) , and other 5 530 used PCR test of vaginal and rectal swabs (double-swab & PCR group) , and GBS detection rates in the groups were compared. Then, from the double-swab & PCR group, 305 cases who were detected with GBS infection and 2 650 without were selected and compared in terms of information possibly related to GBS infection collected from the medical records, by which potential intrapartum risk factors for GBS infection were identified exploratively. Furthermore, 294 of the above-mentioned 305 cases who also underwent vaginal microbiome test were selected, and compared with a random sample of 367 of the above-mentioned 2 650 cases who also underwent vaginal microbiome test, to analyze the association of vaginal microbiota status with GBS infection.

The GBS detection rates in single-swab culture group, double-swab culture group, and double-swab & PCR group were 5.94% (266/4 479) , 8.07 (100/1 239) , and 10.31% (570/5 530) , respectively. The GBS detection rate was lower in single-swab culture group than that of other two groups (P<0.017) . And double-swab & PCR group had a higher GBS detection rate than did double-swab culture group (P<0.017) . Multiple Logistic regression analysis showed that grade Ⅲ or Ⅳ vaginal cleanliness was closely associated with the prevalence of GBS infection in pregnancy〔OR=3.005, 95%CI (1.220, 7.403) , P=0.017〕.

PCR test of both vaginal and rectal swabs could increase the GBS detection rate. Vaginitis is a major high-risk factor associated with GBS infection during pregnancy, which needs to be addressed in the process of diagnosis and treatment.

探讨妊娠期GBS感染的影响因素。

选取2017年1月至2021年8月于北京大学国际医院妇产科进行GBS筛查的孕晚期孕妇11 248例作为研究对象，按不同的采样和检测方法将研究对象分为单拭子-培养法组（n=4 479）、双拭子-培养法组（n=1 239）和双拭子-PCR法组（n=5 530），比较三组GBS检出率。另选取2019年2月至2021年8月于北京大学国际医院进行双拭子-PCR法筛查GBS阳性的孕妇305例，选取同期、同方法检测GBS阴性的孕妇2 650例，查询病历并记录相关资料，分析产时高危因素对GBS感染的影响。选取双拭子-PCR法筛查中GBS阳性同时在妊娠期进行了阴道微生态状态检测的孕妇294例，采用随机数字表法从双拭子-PCR法筛查GBS阴性同时在妊娠期进行了阴道微生态状态检测的孕妇中抽取孕妇367例，分析阴道微生态状态对GBS感染的影响。

单拭子-培养法组GBS阳性率为5.94%（266/4 479），双拭子-培养法组GBS阳性率为8.07%（100/1 239），双拭子-PCR法组GBS阳性率为10.31%（570/5 530），其中双拭子-培养法组和双拭子-PCR法组GBS阳性率高于单拭子-培养法组，双拭子-PCR法组GBS阳性率高于双拭子-培养法组（P<0.017）。多元Logistic回归分析结果显示，阴道清洁度Ⅲ~Ⅳ度是孕妇发生GBS感染的危险因素〔OR=3.005，95%CI（1.220，7.403），P=0.017〕。

进行双拭子采样并采用PCR检测方法可以提高GBS阳性率检出率，妊娠期阴道炎是GBS感染的高危因素，需在诊疗过程中更多关注。