青海鼠疫菌株的毒力因子及某些相关因素的研究

对青海692株鼠疫菌的毒力因子研究结果表明,FI 和 PstI 全部为阳性;Pgm 和 VW 性质不太稳定,其阴性率分别为7.4%和2.6%。由于毒力因子是由质粒介导的,因此对某些毒力因子和质粒的关系进行了观察,发现在19株 VW~-菌株中仅3株失去45Md 质粒,多数菌株质粒无变化。Pgm~-菌株多分离自蚤类(斧形盖蚤和谢氏山蚤),由于这类菌株不易形成菌栓,它们难以引起动物间鼠疫流行。对两种毒力因子同时发生变异的菌株推测其毒力将会减弱。

Research on virulence factors and certain relevances of Y.Pestis in Qinghai

The detection of virulence factors in 692 strains of Y.pestis in Qinghai has showed that Fraction I antigen(FI) and pesticin(PstI) were all positive in the tested strains,and the pigmentation and Vw antigen production hada labile state with negative rates of 7.6% and 2.6%,respectively.The relevance of plasmid to the virulence factorswas also studied.The result released that among 19 Vw-negative strains,only 3 ones lost the 45 MD plasmid,andthe rest had no visiable changs in plasmids.Most of Pgm-negative strain were isolated from flea species(mainlyOropsylla silantiew and Callopsylla dolabris),which were considered to be unable to cause the spread of plague a-mong animals due to uneasiness of the bacteris blockage in the flea.It was supposed that simultaneous mutations oftwo virulence factors would lead to a diminution in virulence.