The Escherichia coli ycbQRST operon encodes fimbriae with laminin-binding and epithelial cell adherence properties in Shiga-toxigenic E. coli 0157:H7

摘要

The human pathogen Shiga-toxigenic Escherichia coil (STEC) O157:H7 contains a ycbQRSTfimbrial-like operon, which shares significant homology to the family of F17 fimbrial biogenesis genes f17ADCG found in enterotoxigenic E. coil. We report that ? growth of STEC O157:H7 strain EDL933 in minimal Mince medium at 37°C and during adherence to epi_thelial cells led to the production of fine peritrichous fimbriae, which were found to be composed of a major subunit of 18 kDa whose N-terminal amino acid sequence matched the predicted protein product of the ycbQ gene; and showed significant homology to the F17a-A fimbrin. Similar to the F17 fimbriae, the purified STEC fimbriae and the recombinant YcbQ protein fused to a His peptide tag bound laminin, but not fibronectin or collagen. Thus, we propose the name E. coli YcbQ laminin-binding fimbriae (ELF) to designate the fimbriae encoded by the ycbQRST operon. The role of ELF as an adherence factor of STEC to cultured epithelial cells was investigated. We provide compelling evidence demonstrating that ELF contributes to adherence of STEC to human intestinal epithelial cells and to cow and pig gut tissue in vitro.