伤寒杆菌耐药质粒pR_(ST98)介导血清杀菌作用抗性的研究

将ｐ Ｒ Ｓ Ｔ９８ 导入不含质粒且对抗菌药物敏感的大肠杆菌、伤寒杆菌，并用十二烷基硫酸钠（ Ｓ Ｄ Ｓ） 消除耐药菌株的ｐ Ｒ Ｓ Ｔ９８ ，计算接合子及 Ｒ 质粒消除前后菌株在人、兔及豚鼠的不同浓度、不同成份血清中的存活率。ｐ Ｒ Ｓ Ｔ９８ 介导其宿主菌对血清杀菌的抗性，但在不同宿主菌中抵抗力不同；补体经典途径及旁路途径均参与血清杀菌过程。ｐ Ｒ Ｓ Ｔ９ ８ 具有多效性，其广泛的宿主性在介导细菌多重耐药的同时，还赋予细菌抵抗血清的杀菌作用，使病原菌致病性增强。

Study on the Serum Resistance Mediated by An Antibiotic Resistance Plasmid from Salmonella Typhi

The purpose of this study was to examine the effect of a 98.6 Mdal antibiotic resistant plasmid from S.typhi(pR ST98 ) on the serum killing of S.typhi and E.coli strains.pR ST98 ,harbouring in S.typhi strain(ST1) was transferred to plasmid-free E.coliK 12 W 1485 and S.typhi strain ST 2.Whereas pR ST98 carried by ST1 was cured by 10% SDS,the vibilities in dilute and nomal human,rabbit and guinea pig serum (NHS,NRS and GPS) were compared.Our result demonstrated that pR ST98 rendered S.typhi and E.coli resistant to killing by NHS,NRS and GPS;the level of resistance was strain dependent and serum dependent;pR ST98 inhibited killing by both the classical and alternative C pathway.Since pR ST98 is a self-transmissible plasmid with a broad host range among the enteric bacilli,the possibility that pR ST98 carries a serum resistance gene is potentially important in infectious disease processes.