基于模拟膀胱动态模型的导尿管源性ESBLs大肠埃希菌生物膜形成和细菌耐药性分析

Escherichia coli biofilm formation in catheter-derived ESBLs based on a simulated bladder dynamic model and bacterial drug resistance analysis

目的 基于模拟膀胱细菌生物膜动态模型,观察导尿管相关性ESBLs大肠埃希菌生物膜形成和细菌耐药性分析。方法 实验菌株共46例,标准菌株ATCC25922(E0)做质控。梅里埃VITEK2.0微生物分析仪鉴定,并做11种抗生素的药敏试验。静态孵育12孔板结晶紫染色法测定细菌生物膜形成能力。构建膀胱细菌生物膜动态孵育系统,结晶紫染色结合光学显微镜,测定细菌生物膜的生长特点。比较多组间生物膜形成平均OD值、生物膜不同表型(阴性或阳性)的耐药率。结果 实验菌株对碳青霉烯类抗生素和替加环素敏感率100%(46/46),对其余抗生素呈现不同程度耐药。静态模型生物膜阳性率89.13%(41/46),生物膜阴性率10.87%(5/46)。动态模型生物膜阳性率95.65%(44/46),生物膜阴性率4.35%(2/46)。动态模型BF阳性株平均OD值显著高于静态模型(P<0.05)。生物膜不同表型对34种抗生素耐药性差异无统计学意义(P>0.05)。结论 ESBLs大肠埃希菌具备生物膜形成能力,生物膜不同表型的耐药性不存在差异;体外动态模拟膀胱细菌生物膜模型可以实现持续感染模拟尿动态培养,并显著促进细菌生物膜生成。

Objective To observe the Escherichia coli(E.coli) biofilm formation from catheter-related E. coli with extended-spectrum β-Lactamases(ESBLs), and analyze the bacterial drug resistance based on a simulated bladder bacterial biofilm dynamic model.Methods A total of 46 experimental strains were obtained. The standard strain ATCC25922(E0) was used as the quality control. Mérieux VITEK2.0 microbiological analyzer was used for bacterial identification. Eleven antibiotic susceptibility tests were carried out. The ability of bacterial biofilm formation was determined by static incubation of 12-well plates with crystal violet staining. A dynamic incubation system for bacterial biofilms of the bladder was constructed. Crystal violet staining combined with light microscopy was used to determine the growth characteristics of bacterial biofilms. The average OD value of biofilm formation and the drug resistance rate of different phenotypes(negative or positive) of biofilms were compared among multiple groups.Results The 46 clinically isolated urinary pathogenic strains were 100% sensitive to carbapenems and tigecycline(46/46). However, the strains were resistant to the remaining antibiotics at various degrees. The positive rate of biofilms in the static model was 89.13%(41/46), and the negative rate of biofilms was 10.87%(5/46). The positive rate of dynamic model biofilms was 95.65%(44/46) and negative rate of biofilms was 4.35%(2/46). The average OD value of bacterial film(BF)-positive strains in the dynamic model was significantly higher than that in the static model(P<0.05). There was no significant difference in the resistance to 34 antibiotics among different phenotypes of biofilms(P>0.05).Conclusion E coli with ESBLs have the ability to form biofilms. There is no difference in the drug resistance of different phenotypes of biofilms. The in vitro dynamic simulated bladder bacterial biofilm model can achieve persistent infection and simulate urinary dynamic culture, and significantly promote the formation of bacterial biofilms.