大肠埃希菌耐药谱型、基因型和生物膜表型关系研究

Study on Relationship between Drug Resistance Pattern,Biofilm Phenotype and Genetic Phenotype in E.coli

以ATCC25922为研究对象,采用改良结晶紫染色,快速银染法和扫描电镜技术对其生物被膜进行定量和定性研究,建立大肠埃希菌生物被膜体外模型,利用优化的模型条件对249株临床分离株进行验证。采用琼脂平板计数法绘制大肠埃希菌浮游菌和被膜菌生长曲线,比较其生长特性的异同。对不同成膜能力的大肠埃希菌临床分离株进行色氨酸定量试验,分析不同培养条件对生物被膜菌胞外基质分泌量的影响。快速银染法和扫描电镜定性研究结果表明,大肠埃希菌形成生物被膜后,形成一种浮游细菌和生物被膜细菌共同分布于同一生存空间内的特殊生理结构;不同稀释度的接种量对细菌生物被膜生物量的变化影响不显著(P>0.05)。249株大肠埃希菌分为强成膜能力、中等成膜能力、弱成膜能力和无成膜能力4个表型,分别占3.21%、18.88%、51.81%、26.10%。

Broth microdilution method was used for antimicrobial agent susceptibility testing of 249 clinical E.coli isolates to 13 antibiotics,such as Enrofloxacin,Florfenicol and Ceftiofur and the data was statisticized by WHONET 5.4 software,and the relationship between drug resistance pattern and biofilm phenotype was analyzed.Meanwhile,ERIC-PCR（Enterobacterial repetitive intergenic consensus-PCR） technique was used for genetic fingerprint of the 64 clinical isolates to elucidate the relationship between biofilm-forming ability and genetic phenotype and provide theoretical basis for molecular genetic mechanisms and molecular epidemiology of E.coli biofilm formation.