Abstract
Type 1 fimbriae (T1F) are well characterised cell surface organelles expressed by Escherichia coli and required for adherence to mannosylated host tissue. They satisfy molecular Koch's postulates as a virulence determinant and a host-adapted role has been reinforced by reports that T1F expression is repressed at submammalian temperatures. Analysis of a group of 136 environmental and animal E. coli isolates that express T1F at 37°C showed that 28% are also capable of expression at 20°C, in a phase variable manner. The heterogeneous proportions varied widely, and although growth temperature impacted the total proportion expressing T1F, there was no direct correlation between growth at 37°C and 20°C, indicative of differences in thermoregulation of the genetic switch (fimS) that controls phase variation. Specificities of the adhesin (FimH) also varied between the isolates: most bound to α-(1-3) mannan and yeast extracts as expected, but some recognised β-(1-4)-mannans and N-linked glycoproteins from plants, and T1F from two of the isolates mediated binding to plant roots. The results expand our view of a well-described adherence factor to show alternative expression profiles and adhesin specificities, which in turn may confer an advantage for certain isolates in alternative hosts and habitats.
Original language | English |
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Pages (from-to) | 1-8 |
Number of pages | 8 |
Journal | FEMS Microbiology Letters |
Volume | 363 |
Issue number | 22 |
DOIs | |
Publication status | Published - Nov 2016 |
Keywords
- Adhesins, Escherichia coli
- Bacterial adhesion
- Cell extracts
- Escherichia coli
- Fimbriae proteins
- Fimbriae, Bacterial
- Glycoproteins
- Mannans
- Mannose
- Plant roots
- Protein binding
- Temperature
- Journal article