鸡源大肠杆菌生物被膜的耐药性分析

Analysis of Drug Resistance of Fowl E.coli Biofilm

为探讨鸡源大肠杆菌生物被膜的耐药机制,采用改进的平板培养法建立鸡大肠杆菌生物被膜体外模型,用液体二倍稀释法分别测定了鸡源大肠杆菌生物被膜菌、浮游菌和脱膜菌对克拉霉素、环丙沙星、磷霉素等13种抗菌药的敏感性,并检测了细菌生物被膜中超广谱β-内酰胺酶的产生情况。结果表明:浮游菌和脱膜菌对同种药物的敏感性几乎相同,而生物被膜菌对同种药物的耐药性比后两者显著增强,并且2株不产超广谱β-内酰胺酶的浮游菌在形成生物被膜后产生了超广谱β-内酰胺酶。由此说明,生物被膜菌的耐药性主要是由于生物被膜这种特殊结构造成的,同时,由于生物被膜的存在,促使了超广谱β-内酰胺酶的产生。生物被膜的形成和超广谱β-内酰胺酶的产生是鸡大肠杆菌生物被膜耐药的两个主要原因。

To investigate the mechanism of drug resistance of fowl E. coli biofilm, the in vitro model of fowl E. coli biofilm was established with the improved flat-board method, and the sensitivity of biofilm, the planktonic and the defilming to thirteen antibacterial agents （including clarithromycin, ciprofloxacin, fosfomycin, etc. ）were determinded by broth double dilution. Meanwhile,ESBLs production was also detected. The result revealed that the planktonic and the defilming had the similar antibiotic susceptibilities, while the biofilm was significantly higher than those above two. Two planktonic non-ESBLs strains could produce ESBLs after becoming biofilm. All these proved that the special structure of biofilm is the fundamental factor of drug resistance of bacterial biofilm, and the existence of biofilm enhances the production of ESBLs. It was concluded that the formation of biofilm and the production of ESBLs are the two key reasons for drug resistance of the fowl E. coli biofilm.