伤寒杆菌耐药质粒pR_(ST98)与细菌在巨噬细胞内存活关系的研究

Studies on the Ability of S.typhi Strains Survival within Macrophages Mediated by Drug Resistant Plasmid

目的 研究伤寒杆菌的不相容性C群接合性耐药质粒 pRST98对其宿主菌在巨噬细胞内存活的影响。方法 用标准系列稀释法检测 3株同源染色体伤寒杆菌———含 pRST98的野生型伤寒菌株STpRST98、经SDS人工消除pRST98的突变体菌株ST(R-)及 pRST98重新导入突变体的接合子 pRST98/ST(R-) ,研究它们在BALB/c小鼠腹腔巨噬细胞M J774A .1内的存活情况。结果 巨噬细胞吞噬后 6 0min内大多数待检菌被杀死 ,但 pRST98宿主菌在巨噬细胞内的活菌数明显高于无此质粒的菌株 (P <0 .0 5 )。结论 pRST98能提高其宿主菌在巨噬细胞内的存活能力。

Objective Whether the conjugational IncC group R plasmid (pR ST98 ),encoding resistance to antimicrobial agents in Salmonella typhi ,contribute to the ability of its host bacteria survival within macrophages was studied.Methods With a standard recovery procedure (log dilution of lysed cells),three chromosomally isogenic strains,i.e.plasmid containing widetype S.typhi strain STpR ST98 ,plasmid artificially cured strain ST(R -) and plasmid re introduced into the cured strain pR ST98 /ST(R -) were compared for their ability to survival within BALB/c mouse macrophage cell MJ 774A.1 .Results There was a rapid initial intracellular destruction of the salmonllae during a 1h phagocytosis reaction,but the numbers of viable bacteria of STpR ST98 and pR ST98 /ST(R -) were higher than that of ST(R -).Conclusions pR ST98 can enhance the ability of S.typhi strains survival within macrophages.