Bacterial fimbriae are an important virulence factor mediating adhesion to both biotic and
abiotic surfaces and facilitating biofilm formation. The expression of type 1 fimbriae of Escherichia
coli is a key virulence factor for urinary tract infections and catheter-associated urinary tract
infections, which represent the most common nosocomial infections. New strategies to reduce
adhesion of bacteria to surfaces is therefore warranted. The aim of the present study was to
investigate how surfaces with different nanotopography-influenced fimbriae-mediated adhesion.
Surfaces with three different nanopattern surface coverages made in polycarbonate were fabricated
by injection molding from electron beam lithography nanopatterned templates. The surfaces were
constructed with features of approximately 40 nm width and 25 nm height with 100 nm, 250 nm,
and 500 nm interspace distance, respectively. The role of fimbriae type 1-mediated adhesion was
investigated using the E. coli wild type BW25113 and ΔfimA (with a knockout of major pilus protein
FimA) and ΔfimH (with a knockout of minor protein FimH) mutants. For the surfaces with
nanotopography, all strains adhered least to areas with the largest interpillar distance (500 nm). For
the E. coli wild type, no difference in adhesion between surfaces without pillars and the largest
interpillar distance was observed. For the deletion mutants, increased adhesion was observed for
surfaces without pillars compared to surfaces with the largest interpillar distance. The presence of
a fully functional type 1 fimbria decreased the bacterial adhesion to the nanopatterned surfaces in
comparison to the mutants.

Adhesion of Escherichia Coli to Nanostructured Surfaces and the Role of Type 1 Fimbriae
Kallas P, Haugen HJ, Gadegaard N, Stormonth-Darling J, Hulander M, Andersson M, Valen H
Nanomaterials 2020, 10, 2247; doi:10.3390/nano10112247