A double, long polar fimbria mutant of Escherichia coli O157

H7 expresses curli and exhibits reduced in vivo colonization

Sonja J. Lloyd, Jennifer M. Ritchie, Maricarmen Rojas-Lopez, Carla A. Blumentritt, Vsevolod Popov, Jennifer L. Greenwich, Matthew K. Waldor, Alfredo Torres

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

Escherichia coli O157:H7 causes food and waterborne enteric infections that can result in hemorrhagic colitis and lifethreatening hemolytic uremic syndrome. Intimate adherence of the bacteria to intestinal epithelial cells is mediated by intimin, but E. coli O157:H7 also possess several other putative adhesins, including curli and two operons that encode long polar fimbriae (Lpf). To assess the importance of Lpf for intestinal colonization, we performed competition experiments between E. coli O157:H7 and an isogenic ΔlpfA1 ΔlpfA2 double mutant in the infant rabbit model. The mutant was outcompeted in the ileum, cecum, and midcolon, suggesting that Lpf contributes to intestinal colonization. In contrast, the ΔlpfA1 ΔlpfA2 mutant showed increased adherence to colonic epithelial cells in vitro. Transmission electron microscopy revealed curli-like structures on the surface of the ΔlpfA1 ΔlpfA2 mutant, and the presence of curli was confirmed by Congo red binding, immunogold-labeling electron microscopy, immunoblotting, and quantitative real-time reverse transcription-PCR (qRT-PCR) measuring csgA expression. However, deletion of csgA, which encodes the major curli subunit, does not appear to affect intestinal colonization. In addition to suggesting that Lpf can contribute to EHEC intestinal colonization, our observations indicate that the regulatory pathways governing the expression of Lpf and curli are interdependent.

Original languageEnglish (US)
Pages (from-to)914-920
Number of pages7
JournalInfection and Immunity
Volume80
Issue number3
DOIs
StatePublished - Mar 2012

Fingerprint

Escherichia coli O157
Epithelial Cells
Enterohemorrhagic Escherichia coli
Congo Red
Hemolytic-Uremic Syndrome
Cecum
Colitis
Operon
Transmission Electron Microscopy
Ileum
Immunoblotting
Reverse Transcription
Electron Microscopy
Rabbits
Bacteria
Food
Polymerase Chain Reaction
Infection

ASJC Scopus subject areas

  • Immunology
  • Microbiology
  • Parasitology
  • Infectious Diseases

Cite this

A double, long polar fimbria mutant of Escherichia coli O157 : H7 expresses curli and exhibits reduced in vivo colonization. / Lloyd, Sonja J.; Ritchie, Jennifer M.; Rojas-Lopez, Maricarmen; Blumentritt, Carla A.; Popov, Vsevolod; Greenwich, Jennifer L.; Waldor, Matthew K.; Torres, Alfredo.

In: Infection and Immunity, Vol. 80, No. 3, 03.2012, p. 914-920.

Research output: Contribution to journalArticle

Lloyd, Sonja J. ; Ritchie, Jennifer M. ; Rojas-Lopez, Maricarmen ; Blumentritt, Carla A. ; Popov, Vsevolod ; Greenwich, Jennifer L. ; Waldor, Matthew K. ; Torres, Alfredo. / A double, long polar fimbria mutant of Escherichia coli O157 : H7 expresses curli and exhibits reduced in vivo colonization. In: Infection and Immunity. 2012 ; Vol. 80, No. 3. pp. 914-920.
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