青藏高原鼠疫自然疫源地鼠疫耶尔森菌病原学研究

Etiology of Yersinia pestis in a plague natural foci of Qinghai-Tibet Plateau

目的了解青藏高原鼠疫自然疫源地鼠疫耶尔森菌(简称鼠疫菌)病原学特征。方法以青藏高原1954-2016年不同地区及宿主、媒介体内分离的1378株鼠疫菌作为实验对象,采用常规技术与分子生物学技术对其进行表型特征、质粒谱、基因组分型等研究,并对青藏高原鼠疫菌病原学、地理分布等特征进行探讨。结果青藏高原鼠疫菌含6个生化型,分别为青藏高原型、祁连山型、冈底斯山型、昆仑山A型、昆仑山B型、川青高原型。本研究发现青藏高原型菌株不仅分布在藏北高原,在藏南地区也有分布,且冈底斯山型在藏南地区也有分布。79.97%(1102/1378)的鼠疫菌有4个毒力因子(荚膜抗原、鼠疫菌素、毒力抗原、色素沉着因子)。青藏高原鼠疫菌株携带有12种质粒,组成17种质粒谱,具有分类属性的最大质粒共有3种,形成了各自相对独立的分布区。鼠疫菌差异片段(DFR)分型的研究表明,1378株菌中5、8、14、19、32和44型为主要基因组型,主要基因组型具有明显的地理分布特征。结论被试菌株均具备青藏高原鼠疫病原体特性。青藏高原鼠疫自然疫源地内主要宿主、传播媒介及鼠疫生态地理景观的多态性可能导致了鼠疫菌生化性状、质粒谱、基因组型等多样性。

Objective To analyze the pathogenic characteristics of Yersinia pestis in a plague natural foci in Qinghai-Tibet Plateau.Methods In this study,1378 strains of Yersinia pestis isolated from different regions,hosts and vectors in Qinghai-Tibet Plateau from 1954 to 2016 were taken as the research objects.Phenotypic characteristics,plasmid spectrum and genotype of the strains were studied by using conventional techniques and molecular biological techniques.The etiology and geographical distribution of the plague were studied.Results There were 6 biochemical types of Yersinia pestis in Qinghai-Tibet Plateau,namely Qinghai-Tibet Plateau,Qilian Mountain,Gangdis Mountain,Kunlun Mountain A,Kunlun Mountain B and Chuanqing Plateau.This study found that the Qinghai-Tibet Plateau type strain was not only distributed in north Tibet Plateau,but also distributed in south Tibet,and the distribution of Gangdis Mountain type strain extended to south Tibet.Four virulence factors(capsule antigen,yersinin,virulence antigen and pigmentation factor)were found in 79.97%(1102/1378)Yersinia pestis.The results also showed that there were 12 kinds of plasmids carried by Yersinia pestis strains in Qinghai-Tibet Plateau,which constituted 17 kinds of plasmid spectrum.There were 3 kinds of the largest plasmids with taxonomic properties,forming their respective relatively independent distribution areas.The study of different regions(DFR)type showed that 5,8,14,19,32 and 44 of 1378 strains were the main genotypes,and the main genome types had obvious geographical distribution.Conclusions All the tested strains have the characteristics of plague pathogen in Qinghai-Tibet Plateau.The polymorphism of the main hosts,vectors and the ecological landscape of plague geography in the plague foci in Qinghai-Tibet Plateau may lead to the diversity of biochemical characters,plasmid spectrum and geno types of Yersinia pestis.