大肠埃希菌多耐药与生物被膜相关性分析

Analysis of the correlation of the multi-drug resistance of Escherichia coli isolates and their biofilm formation

目的探讨细菌耐药程度与细菌生物被膜（BBF）之间的相关性。方法收集临床分离的大肠埃希菌药物敏感株29株,单耐药菌株21株,多耐药菌株60株,采用银染法,以＂＋＂作为BBF量化指标,激光共聚焦显微镜层扫BBF厚度,每个视野扫描8-32层,求平均值。同时采用扫描电镜观察BBF生长情况。结果银染结果药物敏感组＂﹣＂有5株、＂＋＂15株、＂2＋＂8株、＂3＋＂1株;单耐药菌株组＂﹣＂有3株、＂＋＂6株、＂2＋＂10株、＂3＋＂1株、＂4＋＂1株;多耐药菌株组＂﹣＂有1株、＂＋＂7株、＂2＋＂15株、＂3＋＂16株、＂4＋＂21株;多耐药组BBF高于药物敏感组和单耐药组（χ2=15.545,P〈0.05）差异有统计学意义。激光共聚焦显微镜层扫多耐药组BBF厚度为（47.97±9.53）μm,药物敏感组和单耐药组分别为（25.91±5.84）μm和（31.84±4.91）μm,多耐药组与药物敏感组和单耐药组比较差异有统计学意义（F=48.70,P〈0.05）。扫描电镜观察BBF生长,药物敏感组细菌多为杆状生长。多耐药菌株组细菌之间黏液样物质明显增多,细菌相互包裹成块状,47株有大块状。单耐药菌株组中有2株大块状。结论多耐药大肠埃希菌BBF量或厚度高于单耐药及药物敏感大肠埃希菌,表明BBF与大肠埃希菌多耐药有关。

Objective To examine the correlation between bacterial drug resistance and bacterial biofilm（BBF）.Methods Clinical isolates of 29 strains of drug-sensitive E.coli,21 strains of single-drug-resistant E.coli,and 60 strains of multi-drug-resistant E.coli were collected.BBF was stained with silver stain and＇＋＇served as a quantitative index.The thickness of the BBF was determined with confocal laser scanning microscopy.In each field,8-32 layers were scanned and the thickness was averaged.Scanning electron microscopy was used to observe BBF growth. ResultsSemiquantitative analysis of the BBF with silver staining indicated that 5of the drug-sensitive strains were ＂-＂,15 were ＂ ＋＂,8were ＂2＋＂,and 1was ＂3＋＂.Three of the single-drug-resistant strains were ＂-＂,6were ＂ ＋＂,10 were ＂ 2＋＂,1was ＂3＋＂,and 1was ＂4＋＂.One of the multi-drug-resistant strains was ＂-＂,7were ＂ ＋＂,15 were ＂2＋＂,16 were ＂3＋＂,and 21 were ＂4＋＂.Semiquantitative analysis of the BBF with silver staining indicated that multi-drug resistant strains had more BBF than the drug-sensitive strains or the single-drug-resistant strains（χ2=15.545,P〈0.05）.Quantitative analysis of the BBF＇s thickness with confocal laser scanning microscopy indicated that the mean thickness of the BBF was（47.97±9.53）μm for multi-drug-resistant strains,（25.91±5.84）μm for drug-sensitive strains,and（31.84±4.91）μm for single-drug-resistant strains.Multi-drug-resistant strains had a thicker BBF than the drug-sensitive strains or the single-drug-resistant strains（F=48.70,P〈0.05）.BBF growth observed with scanning electron microscopy indicated that most of the drug-sensitive strains had rod growth.Multi-drug-resistant strains had a marked increase in mucus-like material and encapsulated cells in clumps.Forty-seven of those strains produced large clumps of cells.Two of the 21single-drug-resistant strains produced large clumps of cells. Conclusion Multi-drug-resistant E.coli had more BFF and thicker BFF than did single-drug-resistant or drug-sensitive E.coli.This indicated that BBF is directly correlated with multi-drug resistance of E.coli.