2012—2017年天津市百日咳鲍特菌株抗原基因特征分析

Characteristics of antigenic genes of Bordetella pertussis in Tianjin, 2012-2017

目的对天津市2012—2017年百日咳临床分离株的主要抗原基因片段进行序列分析,比较与疫苗株的差异。方法采集天津2012—2017年百日咳临床诊疗患者鼻咽拭子进行百日咳鲍特菌培养,对所得菌株进行ptxS1、prn、fim2、fim3及fha B抗原基因的PCR扩增,与疫苗株CS株进行基因序列比对分析,应用MEGA7分析软件构建系统进化树。结果127份鼻咽拭子分离到19株百日咳鲍特菌,与疫苗株相比,ptxS1基因核苷酸同源性为99.6%,临床株全部为ptxS1A基因型,而疫苗株为ptxS1B型;prn基因同源性为99.7~100%,其中18株与疫苗株同为prn1基因型,1株为prn2基因型;fim2、fim3、fha B分离株与疫苗株的同源性均为100%,为fim2-1/fim3A/fha B1基因型。结论本次研究获取的天津市百日咳鲍特菌临床分离株ptxS1和prn基因与疫苗株相比存在差异,为新的疫苗研发及百日咳防治策略的改善提供依据。

Objective To analyze the gene sequences of major antigens of Brodetella pertussis isolates from 2012 to 2017 in Tianjin, so as to identify the differences compared with the vaccine strain. Methods Brodetella pertussis was isolated from nasopharyngeal swabs collectted from clinically diagnosed patients of pertussis in recent six years in Tianjin,and was amplified by PCR for the genes of ptxS1, prn, fim2, fim3, and fha B, the differences were identified by gene sequence analysis between the isolates and the vaccine strain of Bordetella pertussis CS, based on the plotted phylogenetic tree. Results A total of 19 Brodetella pertussis strains were isolated from 127 nasopharyngeal swabs of pertussis patients. The nucleotide homology of ptxS1 gene was 99.6% compared with the vaccine strain, the clinical strains were all ptxS1A genotype,but the vaccine strain was ptxS1B. The homology of prn gene was 99.7%-100%, 18 strains of which were the prn1 genotype as the same as the vaccine strain, and one strains was the prn2 genotype. The homology of fim2, fim3, fha B were 100% between isolates and the vaccine strain. Conclusion The genes of ptxS1 and prn of modern pertussis isolates are different from the vaccine strain in Tianjin. It may be a foundation for new vaccine research and pertussis control strategies improvement.