Trautner Barbara W, Cevallos Manuel E, Li Huaiguang, Riosa Sarah, Hull Richard A, Hull Sheila I, Tweardy David J, Darouiche Rabih O
Division of Infectious Diseases, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA.
J Infect Dis. 2008 Sep 15;198(6):899-906. doi: 10.1086/591093.
In vitro, urinary catheter colonization by avirulent Escherichia coli 83972 impedes subsequent catheter colonization by a variety of uropathogenic organisms. However, E. coli 83972 shows a low efficacy of adherence to silicone urinary catheter material, possibly because the fim operon encoding adhesive type 1 fimbriae is incomplete. We hypothesized that improving the catheter adherence of E. coli 83972 would improve its bacterial interference properties.
We created adhesive mutants by transforming wild-type E. coli 83972 with fim(+) plasmids. Adherence to urinary catheters and ability to prevent uropathogenic E. coli from colonizing urinary catheters were studied by use of a sonication assay.
The addition of a single-copy fim(+) plasmid increased adherence to urinary catheters 10-fold, and addition of an 18-copy fim(+) plasmid increased adherence 100-fold. The more adherent 18-copy fim(+) plasmid strain was more effective at blocking catheter colonization by pathogenic E. coli than was the wild-type parental strain. Neither Deltafim nor fim(+) E. coli 83972 adhered to shed urinary epithelial cells.
Our results indicate that improving urinary catheter adherence augments the bacterial interference capabilities of benign E. coli 83972. Increased expression of type-1 fimbriae may enhance bacterial interference without conferring virulence on E. coli 83972.
在体外，无毒力的大肠杆菌83972在导尿管上的定植会阻碍随后多种尿路致病微生物在导尿管上的定植。然而，大肠杆菌83972对硅胶导尿管材料的黏附效力较低，这可能是因为编码1型菌毛的fim操纵子不完整。我们推测，提高大肠杆菌83972对导尿管的黏附性将改善其细菌干扰特性。
我们通过用fim(+)质粒转化野生型大肠杆菌83972来构建黏附突变体。通过超声处理试验研究了其对导尿管的黏附性以及防止尿路致病性大肠杆菌在导尿管上定植的能力。
添加单拷贝fim(+)质粒使对导尿管的黏附性增加了10倍，添加18拷贝fim(+)质粒使黏附性增加了100倍。黏附性更强的18拷贝fim(+)质粒菌株在阻断致病性大肠杆菌在导尿管上的定植方面比野生型亲本菌株更有效。缺失fim的大肠杆菌83972和fim(+)大肠杆菌83972均不黏附脱落的尿路上皮细胞。
我们的结果表明，提高对导尿管的黏附性可增强良性大肠杆菌83972的细菌干扰能力。1型菌毛表达的增加可能增强细菌干扰能力，而不会赋予大肠杆菌83972毒力。
