围生期孕妇B族链球菌筛查方法学探讨及血清型耐药性分析

Screening methodology and serotype and drug resistance analysis of group B streptococcus in perinatal pregnant women

目的探讨围生期孕妇感染B族链球菌(GBS)最优的筛查方法,分析其血清型和耐药性及临床结局。方法选取西安市第一医院2018年1月至2020年8月产科门诊及住院收治的35~37周孕妇874例为研究对象,采集生殖道-直肠分泌物,采用荧光定量PCR法和显色培养加鉴定法筛查GBS,分析2种方法的阳性检出率,乳胶凝集试验检测GBS菌株的血清型,最低抑菌浓度(MIC)法检测细菌对常用抗菌药物的耐药性,分析GBS感染对孕妇临床结局的影响。结果874例孕妇的待检标本中,荧光定量PCR法阳性检出率为8.92%,显色培养加鉴定法阳性检出率为6.41%,差异有统计学意义(P<0.05)。通过临床随访,874例孕妇中有33例发生胎儿窘迫、孕妇败血症、新生儿败血症、早产、胎膜早破等异常情况,其中28例经荧光定量PCR法检测GBS为阳性,19例经显色培养加鉴定法检测GBS为阳性,差异有统计学意义(P<0.05)。78株孕妇定植的GBS共检出4种血清型,分别为Ⅲ型(51.28%)、Ⅰb型(20.51%)、Ⅰa型(16.67%)、Ⅴ型(11.54%)。GBS对万古霉素、利奈唑胺、替加环素、头孢吡肟、头孢曲松、氨苄西林、青霉素、四环素敏感性较高,分别为100.00%、100.00%、100.00%、100.00%、100.00%、100.00%、100.00%、82.05%,对克林霉素、左氧氟沙星、红霉素敏感性较低,分别为50.00%、50.00%、0.00%。克林霉素、左氧氟沙星耐药性与血清型差异有统计学意义(P<0.05),血清型Ⅲ、Ⅰb、Ⅴ型耐药性较高。结论荧光定量PCR法快速、准确,阳性检出率高,对检测围生期妇女GBS感染更有价值。西安地区孕妇GBS定植、感染GBS血清型分布前4位为Ⅲ型、Ⅰb型、Ⅰa型、Ⅴ型;GBS对红霉素、左氧氟沙星、克林霉素耐药率较高,耐药菌株在Ⅲ型、Ⅰb型、Ⅴ型分离株中广泛流行、临床应根据药敏结果合理使用抗菌药物,有效预防孕妇GBS感染。

Objective To explore the optimal screening method for group B Streptococcus(GBS)infection in perinatal women,and analyze its serotype,drug resistance and clinical outcomes.Methods A total of 874 pregnant women of 35-37 weeks in the First Hospital of Xi′an from January 2018 to August 2020 were selected.The genital tract and rectum secretions were collected.Fluorescent quantitative PCR and chromogenic culture plus identification were used to screen GBS,and the positive detection rates of the two methods were analyzed.The serotype of GBS was detected by latex agglutination test.The minimum inhibitory concentration(MIC)method was used to detect the drug resistance of bacteria to commonly used antibiotics.The impact of GBS infection on clinical outcomes of pregnant women was analyzed.Results In 874 samples,the positive rate of fluorescent quantitative PCR was 8.92%,and the positive rate of chromogenic culture plus identification was 6.41%,the difference was statistically significant(P<0.05).Through clinical follow-up,33 of 874 pregnant women had fetal distress,sepsis of pregnant women,neonatal sepsis,premature delivery,premature rupture of membranes and other abnormalities,of which 28 cases were positive by fluorescent quantitative PCR,19 cases were positive by chromogenic culture plus identification,the difference was statistically significant(P<0.05).Four types of GBS were detected in 78 pregnant women,which were typeⅢ(51.28%),typeⅠb(20.51%),typeⅠa(16.67%)and typeⅤ(11.54%).The sensitivity of GBS to vancomycin,linezolid,tigecycline,cefepime,ceftriaxone,ampicillin,penicillin and tetracycline was 100.00%,100.00%,100.00%,100.00%,100.00%,100.00%,100.00 and 82.05%,respectively,while the sensitivity to clindamycin,levofloxacin and erythromycin were 50.00%,50.00%and 0.00%,respectively.The drug resistance of clindamycin,levofloxacin and serotypes were significantly different(P<0.05),and serotypesⅢ,Ⅰb andⅤhad higher drug resistance.Conclusion Fluorescent quantitative PCR is rapid,accurate and has a high positive detection rate.It is more valuable for the detection of GBS infection in perinatal women.The top four serotypes of GBS colonization and infection in pregnant women in Xi′an were typeⅢ,typeⅠb,typeⅠa and typeⅤ.The resistance rate of GBS to erythromycin,levofloxacin and clindamycin is high.The resistant strains are widely prevalent in typeⅢ,typeⅠb and typeⅤstrains.The clinical use of antibiotics should be based on the drug sensitivity results to effectively prevent GBS infection in pregnant women.