四株临床分离百日咳鲍特菌主要抗原基因序列分析

Characteristics of the antigenic genes of four clinical Bordetella pertussis strains

目的 了解石家庄地区分离的百日咳鲍特菌4种抗原基因百日咳毒素S1亚单位（ptxS1）、外膜蛋白（Prn）、凝集素2（Fim2）和凝集素3（Fim3）的基因特征.方法 收集4株临床分离的百日咳鲍特菌,这4株菌于2002年分离自河北石家庄地区.分别对这4株菌的ptxS1、Prn、Fim2、Fim3主要抗原基因进行PCR扩增和测序,并与我国的百日咳鲍特菌疫苗生产株抗原基因序列以及GenBank中收录的百日咳基因序列进行比较、分析.结果 序列分析显示,新近分离的4株菌的S1基因亚型与我国疫苗生产菌株不同,均为A亚型,发现3种Prn基因亚型和3种Fim3基因亚型,核苷酸和氨基酸序列与我国疫苗生产菌株同源性均在99%以上.基因进化树显示与其他菌株的同源性也较高.结论 我国的临床分离菌株与疫苗生产菌株的主要抗原基因序列存在一定变异,为百日咳的流行病学研究和疫苗的研制积累理论依据.

Objectives To analyze the characteristics of antigenic genes of clinical Bordetella pertussis strains recently isolated by analyzing the sequence of pertussis toxin S1 subunit（ptxS1） , pertactin （Prn） , fimbriae 2 （Fim2） and fimbriae 3 （Fim3 ） genes of four clinical isolates. Methods The 4 clinical isolates were collected in 2002 in Shijiazhuang of Hebei province. Four strains were isolated from pertussis patient＇s nasopharyngeal aspirate. ptxS1, Prn, Fim2 and Fim3 genes of these strains were amplified and sequenced. The sequences of those genes were compared with those of the isolates in GenBank and the isoaltes used in the production of pertussis vaccine in China. Results The results of the gene sequencing showed the four clinical isolates belonged to ptxS1 A type, which were different from those in vaccine strains. In addition, three Prn and three Fim＇3 variants were observed in the four clinical isolates. Sequence analysis showed that the nucleotide sequence and deduced amino acid sequence of those strains had more than 99% identity with those in vaccine strains. The phylogenetic trees of those genes also showed these strains had a higher level of similarity with other Bordetella pertussis strains. Conclusion The four clinical isolates are different from vaccine strains in four antigenic genes, which laid a foundation for further studies on pertussis epidemiology,quality control and development of pertussis vaccine in China.