Increased Expression of Type‐1 Fimbriae by NonpathogenicEscherichia coli83972 Results in an Increased Capacity for Catheter Adherence and Bacterial Interference

Abstract

Background 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. Methods 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. Results 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 Δfim nor fim+ E. coli 83972 adhered to shed urinary epithelial cells. Conclusions 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.

Escherichia coli Isolates Causing Asymptomatic Bacteriuria in Catheterized and Noncatheterized Individuals Possess Similar Virulence Properties

“…Type 1 fimbriae, as determined by yeast agglutination, were expressed by the majority of the ABU and CA-ABU E. coli strains. This fimbrial type, unlike P fimbriae, is associated with catheter colonization and persistence in the catheterized urinary tract (28,41). Furthermore, the introduction of a plasmid containing type 1 fimbrial genes increased catheter adherence of ABU strain 83972 up to 100-fold and improved its ability to prevent colonization by pathogenic E. coli (41).…”

“…Although the molecular mechanisms of biofilm formation by E. coli in the catheterized urinary tract are not fully understood, surface adhesins such as type 1 fimbriae, type 3 fimbriae, and curli have been shown to contribute to biofilm growth (28,29,41,43). In contrast, ABU E. coli strains are often associated with poor epithelial cell adhesion properties, and thus, the role of biofilm growth in colonization by these strains is less clear.…”

Nanoscale surface modification favors benign biofilm formation and impedes adherence by pathogens

“…In vitro and in vivo we have observed that the adherence of E. coli 83972 to unmodified silicone urinary catheters is low in comparison to the adherence of urinary pathogens (17–19). Furthermore, we have demonstrated that we can increase adherence of E. coli 83972 to catheter surfaces by manipulating expression of type 1 fimbriae, and increased surface adherence leads to increased ability to block pathogen adherence to urinary catheters (17).…”

Surfaces presenting α-phenyl mannoside derivatives enable formation of stable, high coverage, non-pathogenic Escherichia coli biofilms against pathogen colonization

“…Both the Escherichia coli 83972 expressing type 1 fimbriae ( fim+ E. coli 83972, strain HU2545) 35 and the challenge pathogenic bacteria, Enterococcus faecalis 210, were provided by Dr. Barbara W. Trautner (Baylor College of Medicine). This strain of E. faecalis was transformed with pMB158GFP to express green fluorescence protein (GFP) that can be observed by fluorescence microscopy.…”