青海省称多县鼠疫菌生化与分子生物学特征分析

摘要

Objective To study the biological characteristics and epidemiological significance of Yersinia pestis in Chengduo County of Qinghai Province,in order to provide scientific basis for plague prevention and control in this area.Methods Thirty one strains of Yersinia pestis isolated from Chengduo County of Qinghai Province from 1980 to 2011 were selected as study subjects.Biochemical test,virulence factors evaluation [Fra1 (F1),pesticin Ⅱ (Pst Ⅱ),virulence antigen (VW),pigmentation (Pgm)] and different region (DFR) genotyping were carried out.Nineteen of the 31 strains Yersinia pestis were selected according to different time,different areas and different hosts to determine their toxicity in mice,MLD ≤ 10 000 was strong toxic strain,10 000 ＜ MLD ＜ 100 000 was moderate toxic strain.Results Among thirty one strains of Yersinia pestis,23 strains were isolated from human,the Himalaya marmot and its fleas and lice,and their biological type was classical,biochemical type was Qinghai-Tibet plateau;21 strains genotype was type 5,1 was type 16,1 was type 32,and they contained all four kinds of virulence factors (F1,Pgm,Pst Ⅱ,VW),and toxicity test showed all strains (14) were strong toxic strains.The rest 8 strains of Yersinia pestis isolated from the Microtus fuscus and its fleas,and their biological type was Microtus,biochemical type was Chuanqing plateau;they could produce F1 and Pgm,of which 87.5％ (7/8) strains could produce Pst Ⅱ,but could not produce VW antigen factor,the genotype was 14,and the toxicity results showed that they were strong (3)and moderate (2) toxic strains.Conclusion The strains separated in Chengduo County of Qinghai Province from 1980 to 2011 have the pathogen characteristics of Qinghai-Tibet plateau plague,they are mainly strong toxic strains;the work on prevention and control of plague should not be neglected.%目的 探讨青海省称多县鼠疫菌株生物学特点及流行病学意义,为该地区的鼠疫防治提供科学依据.方法 以1980-2011年称多县分离的31株鼠疫菌株作为实验对象,进行生化试验、毒力因子鉴定[荚膜抗原(F1)、色素沉着因子(Pgm)、鼠疫杆菌素Ⅰ(PstⅠ)、毒力抗原因子(VW)]、差异片段(DFR)分型,并根据不同时间、不同地区、不同宿主选取19株菌株进行小白鼠毒力测定,以最小致死量(MLD)表示,MLD≤10 000为强毒菌,10 000＜ MLD＜100 000为中等毒力菌.结果 31株被试菌株中,有23株是从喜马拉雅旱獭及其媒介蚤、虱和人体分离的,生物型为古典型,生化型为青藏高原型;21株基因型为5型,1株为16型,1株为32型;F1、Pgm、PstⅡ、VW 4种毒力因子俱全,毒力测定结果为强毒菌(14株).有8株是从青海田鼠及其媒介蚤分离的,生物型为田鼠型,生化型为川青高原型;均能产生F1及Pgm,其中87.5％(7/8)的菌株可以产生Pst Ⅱ,均不能产生VW抗原因子;基因型为14型,毒力测定结果为强毒菌(3株)、中等毒力菌(2株).结论 青海省称多县1980-2011年鼠疫菌株具备青藏高原鼠疫病原体特性,鼠疫菌毒力强,鼠疫防治工作不容松懈.