云南西双版纳百日咳博德特氏菌分离株抗原基因特征分析

Antigenic gene characteristics of Bordetella pertussis isolates from child patients in Xishuangbanna,Yunnan province:a comparative analysis

目的比对云南省西双版纳地区新的百日咳临床分离株与疫苗株及其他地区流行的百日咳博德特氏菌基因特征,为百日咳的防控提供科学依据。方法对2019年10—12月从云南省西双版纳州人民医院采集的4株百日咳临床分离流行株进行全基因组测序,利用MegAlign 7.1.0软件确定分离株的ptxP、ptxA、prn、fim3基因型,并与我国无细胞百日咳疫苗株CS株以及NCBI数据库中公开的其他国家和地区流行的百日咳博德特氏菌ptxP、ptxA、prn、fim3抗原基因特征进行对比分析;使用RAxML软件基于对28株百日咳博德特氏菌全基因组SNP构建系统发育树。结果云南西双版纳4株百日咳临床分离株BP-L1、BP-L2、BP-L3、BP-L4基因组比CS株多产生了33~36个插入序列引起的基因重排。4株百日咳临床分离流行株的ptxP、ptxA、prn、fim3基因序列与CS株相似度在99.2%~100%。系统发育树结果显示,CS株与参考株TohamaⅠ聚为1支,形成独立进化分支;近年来全球流行的百日咳博德特氏菌分成2个聚类,BP-L1、BP-L4与多数欧美国家百日咳博德特氏菌聚为1支,主要为ptxP3/ptxA1/prn2型菌株,BP-L2、BP-L3与亚洲国家和地区的流行的百日咳博德特氏菌聚为1支,主要是ptxP1/ptxA1/prn1型菌株。结论云南西双版纳临床分离株与疫苗株相比,主要毒力蛋白基因和进化分支发生了明显变化,与近年来国际流行的百日咳博德特氏菌遗传进化一致。

Objective To compare genetic characteristics of Bordetella pertussis isolates from child patients in Xishuangbanna,Yunnan province with those of vaccine isolate and Bordetella pertussis isolates from patients of other regions for providing evidence to pertussis prevention and control.Methods Four Bordetella pertussis strains(named BPL1,BP-L2,BP-L3,BP-L4)were isolated from nasopharyngeal swab specimens of child pertussis patients in the People’s Hospital of Xishuangbanna Prefecture,Yunnan province during October-December 2019 and the whole genome of the isolated strains were sequenced;the ptxP,ptxA,prn,fim3 genotype of the isolated strains were determined with MegAlign 7.1.0.According to the gene sequences published in National Center for Biotechnology Information(NCBI)database,the genotypes of the isolated strains were compared with those of CS strain of acellular pertussis vaccine innoculated in China and of the Bordetella pertussis strains prevalent in other countries and regions.Phylogenetic trees were constructed using RAxML software based on single nucleotide polymorphism(SNP)of 28 Bordetella pertussis strains.Results Gene rearrangement due to 33-36 insertion sequences of the four isolated strains were identified in comparison with those of the CS strain.The similarity between ptxP,ptxA,prn,fim3 gene sequence of the isolated strains and CS strain was 99.2%-100%.The results of phylogenetic tree showed that CS strain and reference strain TohamaⅠclustered into a branch and formed an independent evolutionary branch.In recent years,Bordetella pertussis,which is prevalent in the world,can be divided into two clusters;the isolated BP-L1 and BP-L4 were clustered with the Bordetella pertussis prevalent in most European and American countries,which mainly included ptxP3/ptxA1/prn2 strains;while,the isolated BP-L2 and BP-L3 were clustered with Bordetella pertussis inducing endemic in Asia and mainly including ptxP1/ptxA1/prn1 strains.Conclusion Compared with the vaccine strains,the main virulence protein genes and evolutionary branches of the Bordetella pertussis strains clinically isolated in Xishuangbanna,Yunnan province changed significantly and the changes are consistent with the genetic evolution trend of the Bordetella pertussis prevalent globally in recent years.