耐药质粒pR_(ST98)在不同种属肠道杆菌间的接合及表达  

The conjugational transfer and antibiotic resistance expression of S.typhi R plasmid (pR_(ST98)) in different enteric bacilli

作　　者：黄瑞[1] 秦爱兰[1] 闻玉梅[2] 

机构地区：[1]苏州医学院微生物学教研室 [2]上海医科大学

出　　处：《中华微生物学和免疫学杂志》2000年第4期323-326,共4页Chinese Journal of Microbiology and Immunology

基　　金：江苏省卫生厅基金!资助项目 (基金编号 :H950 7)

摘　　要：目的　研究伤寒杆菌耐药质粒pRST98在不同种属肠道杆菌间 (大肠杆菌、伤寒杆菌、鼠伤寒杆菌及痢疾杆菌 )互相接合传递的规律及表达。方法　以 3株携带不相容性C群 (IncC)pRST98的伤寒杆菌作供体 ,用传统及改良的两种接合转移试验方法 ,研究其在肠道杆菌间的传递及耐药标志的表达 ,并用核酸内切酶对供体菌及受体接合子的R质粒进行分析。结果　pRST98能在 4种肠道杆菌间传递 ;但在不同种属中R质粒接合难易程度不同 ;同一R质粒在不同宿主菌中耐药标志的表达亦有差异。结论　质粒的可传递性给阻断耐药性的传播和疾病的防治带来很大困难 ,大肠杆菌在一定条件下可将耐药质粒传递给伤寒杆菌等肠道致病菌。正常菌群中庞大的耐药基因库是致病性耐药菌株流行的潜在危险 ;同一质粒在不同宿主菌中耐药标志的差异显示出耐药质粒表达的多样性和复杂性。Objective To study the conjugational transfer and antibiotic resistance expression of pR ST98 in different enteric bacilli(including E.coli, S.typhi, S.typhimurium and S.flexneri ). Methods The antimicrobial resistance of 13 strains of enteric bacilli were tested against 13 different antimicrobial agents by means of Kirby-Bauer disc agar diffusion. Their plasmid profiles were also determined. In the conjugation test, 3 strains of clinical isolated multiresistant S.typhi harbouring pR ST98 were tested for the ability to transfer their R plasmids to a plasmid-free laboratory strain of E.coli K 12 W 1485 Rif r . Thereafter, E.coli K 12 W 1485 receiving pR ST98 were used as dornors, while the sensitive and resistant strains of E.coli, S.typhi, S.typhimurium and S.flexneri as recipients for conjugation. Antibiotic susceptibility, plasmid and restriction enzyme analysis of the donors and transconjugants were used for confirmation of the results. Results The pR ST98 could transfer among E.coli, S.typhi, S.typhimurium and S.flexneri, but in different genera the conjugal transfer conditions were different and the resistant markers coded by the same pR ST98 in different strains varied. Conclusions pR ST98 could be transferred from S.typhi to E.coli and then to sensitive and resistant pathogenic bacilli. It is very difficult to block and prevent the spreading of antimicrobial resistance. The varied expression of pR ST98 in different strains demonstrated the diversity and complexity of the R plasmid.

关 键 词：耐药质粒 肠道杆菌 接合传递 耐药标志 

分 类 号：R378[医药卫生—病原生物学]