Mat fimbriae promote biofilm formation by meningitis-associated Escherichia coli.
The mat (or ecp) fimbrial operon is ubiquitous and conserved in Escherichia coli, but its functions remain poorly described. In routine growth media newborn meningitis isolates of E. coli express the meningitis-associated and temperature-regulated (Mat) fimbria, also termed E. coli common pilus (ECP), at 20 degrees C, and here we show that the six-gene (matABCDEF)-encoded Mat fimbria is needed for temperature-dependent biofilm formation on abiotic surfaces. The matBCDEF deletion mutant of meningitis E. coli IHE 3034 was defective in an early stage of biofilm development and consequently unable to establish a detectable biofilm, contrasting with IHE 3034 derivatives deleted for flagella, type 1 fimbriae or S-fimbriae, which retained the wild-type biofilm phenotype. Furthermore, induced production of Mat fimbriae from expression plasmids enabled biofilm-deficient E. coli K-12 cells to form biofilm at 20 degrees C. No biofilm was detected with IHE 3034 or MG1655 strains grown at 37 degrees C. The surface expression of Mat fimbriae and the frequency of Mat-positive cells in the IHE 3034 population from 20 degrees C were high and remained unaltered during the transition from planktonic to biofilm growth and within the matured biofilm community. Considering the prevalence of the highly conserved mat locus in E. coli genomes, we hypothesize that Mat fimbria-mediated biofilm formation is an ancestral characteristic of E. coli.
Lehti
Timo A
TA
General Microbiology, Department of Biosciences, FI-00014 University of Helsinki, Finland.
Bauchart
Philippe
P
Institute for Molecular Infection Biology, University of Würzburg, D-97080 Würzburg, Germany.
Heikkinen
Johanna
J
General Microbiology, Department of Biosciences, FI-00014 University of Helsinki, Finland.
Hacker
Jörg
J
Robert Koch-Institute, D-13353 Berlin, Germany.|Institute for Molecular Infection Biology, University of Würzburg, D-97080 Würzburg, Germany.
Korhonen
Timo K
TK
General Microbiology, Department of Biosciences, FI-00014 University of Helsinki, Finland.
Dobrindt
Ulrich
U
Institute for Molecular Infection Biology, University of Würzburg, D-97080 Würzburg, Germany.
Westerlund-Wikström
Benita
B
General Microbiology, Department of Biosciences, FI-00014 University of Helsinki, Finland.
D001422:Bacterial Adhesion; D018441:Biofilms / Q000254:growth & development*; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D010861:Fimbriae, Bacterial / Q000378:metabolism*; D005798:Genes, Bacterial; D020814:Meningitis, Escherichia coli / Q000382:microbiology; D008969:Molecular Sequence Data; D005810:Multigene Family; D017384:Sequence Deletion
D029968:Escherichia coli Proteins