Contribution of the Ler- and H-NS-regulated long polar fimbriae of Escherichia coli O157

H7 during binding to tissue-cultured cells

Alfredo Torres, Terry M. Slater, Shilpa D. Patel, Vsevolod Popov, Margarita M P Arenas-Hernández

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

The expression of the long polar fimbriae (LPF) of enterohemorrhagic Escherichia coli (EHEC) O157:H7 is controlled by a tightly regulated process, and, therefore, the role of these fimbriae during binding to epithelial cells has been difficult to establish. We recently found that histone-like nucleoid-structuring protein (H-NS) binds to the regulatory sequence of the E. coli O157:H7 lpf1 operon and "silences" its transcription, while Ler inhibits the action of the H-NS protein and allows lpf1 to be expressed. In the present study, we determined how the deregulated expression of LPF affects binding of EHEC O157:H7 to tissue-cultured cells, correlating the adherence phenotype with lpf1 expression. We tested the adherence properties of EHEC hns mutant and found that this strain adhered 2.8-fold better than the wild type. In contrast, the EHEC ler mutant adhered 2.1-fold less than the wild type. The EHEC hns ler mutant constitutively expressed the lpf genes, and, therefore, we observed that the double mutant adhered 5.6-fold times better than the wild type. Disruption of lpfA in the EHEC hns and hns ler mutants or the addition of anti-LpfA serum caused a reduction in adhesion, demonstrating that the increased adherence was due to the expression of LPF. Immunogold-labeling electron microscopy showed that LPF is present on the surface of EHEC lpfA+ strains. Furthermore, we showed that EHEC expressing LPF agglutinates red blood cells from different species and that the agglutination was blocked by the addition of anti-LpfA serum. Overall, our data confirmed that expression of LPF is a tightly regulated process and, for the first time, demonstrated that these fimbriae are associated with adherence and hemagglutination phenotypes in EHEC O157:H7.

Original languageEnglish (US)
Pages (from-to)5062-5071
Number of pages10
JournalInfection and Immunity
Volume76
Issue number11
DOIs
StatePublished - Nov 2008

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Enterohemorrhagic Escherichia coli
Escherichia coli O157
Histones
Cultured Cells
Proteins
Phenotype
Agglutination
Hemagglutination
Operon
Serum
Electron Microscopy
Erythrocytes
Epithelial Cells

ASJC Scopus subject areas

  • Immunology
  • Microbiology
  • Parasitology
  • Infectious Diseases

Cite this

Contribution of the Ler- and H-NS-regulated long polar fimbriae of Escherichia coli O157 : H7 during binding to tissue-cultured cells. / Torres, Alfredo; Slater, Terry M.; Patel, Shilpa D.; Popov, Vsevolod; Arenas-Hernández, Margarita M P.

In: Infection and Immunity, Vol. 76, No. 11, 11.2008, p. 5062-5071.

Research output: Contribution to journalArticle

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