不同来源产毒性大肠杆菌的毒力型、耐药性及质粒分析

Virulence Types Resistance and Plasmid Patterns of Enterotoxigenic Escherichia Coli Isolated from Different Specimens

本研究对从广州郊区某乡的腹泻病人、健康人及环境（包括猪、鸡和环境）中分离到的产毒性大肠杆菌（ETEC）菌株进行了毒力型、耐药性及质粒分析。结果表明，病人ETEC株含LT或STp较多，环境株含LT较多。比较三种来源菌株对20种临床常用抗菌药物的耐药性，病人株的耐药谱最广，耐药率也最高；其次为环境株。根据耐药谱，可把大多数菌株（94％）分为6个型．不同来源ETEC株的优势耐药型有所不同，但不同毒力型ETEC株的耐药谱无明显不同。91．6％（55／60）的ETEC殊含有质粒，与正常大肠杆菌（78．6％）相近，最常见的质粒有2．2～2．6Md、3．3～4．5Md和＞20Md三种，ETEC株含＞20Md质粒显著高于正常大肠杆菌。未发现质粒谱与ETEC毒力型及耐药谱之间有明显的关系。

In this study, 60 strains of FTEC isolated from diarrhoeal patients, healthy people,porcine,chicken and environment in the suburbs of Guangzhou were subrnitted to virulence genes,antibiotic resistance and plasmid profile analysis. Heat-labile toxin(LT) and heat-stable toxin I a(STp) were major virulence factors of ETEC strains isolated from patients. LT was frequently found in the isolates of environrnent. Drug resistance patterns to twenty antimicrobial drugs were differnet among three original strains. Patient's strains had higher rate of drug resistance than that from healthy people and environrnent. 91. 6% of ETEC strains were found to harbour at least one plasrnid. ETEC strains harboured larger than 20Md plasmid frequently than normal E.coli. No obvious relationship was found between plasmid patterns and enterotoxin types or drug resistance patterns.