Characterization of fimbriae produced by enteropathogenic Escherichia coli.
Enteropathogenic Escherichia coli (EPEC) express rope-like bundles of filaments, termed bundle-forming pili (BFP) (J. A. Girón, A. S. Y. Ho, and G. K. Schoolnik, Science 254:710-713, 1991). Expression of BFP is associated with localized adherence to HEp-2 cells and the presence of the EPEC adherence factor plasmid. In this study, we describe the identification of rod-like fimbriae and fibrillae expressed simultaneously on the bacterial surface of three prototype EPEC strains. Upon fimbrial extraction from EPEC B171 (O111:NM), three fimbrial subunits with masses of 16.5, 15.5, and 14.7 kDa were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Their N-terminal amino acid sequence showed homology with F9 and F7(2) fimbriae of uropathogenic E. coli and F1845 of diffuse-adhering E. coli, respectively. The mixture of fimbrial subunits (called FB171) exhibited mannose-resistant agglutination of human erythrocytes only, and this activity was not inhibited by alpha-D-Gal(1-4)-beta-Gal disaccharide or any other described receptor analogs for P, S, F, M, G, and Dr hemagglutinins of uropathogenic E. coli, which suggests a different receptor specificity. Hemagglutination was inhibited by extracellular matrix glycoproteins, i.e., collagen type IV, laminin, and fibronectin, and to a lesser extent by gangliosides, fetuin, and asialofetuin. Scanning electron microscopic studies performed on clusters of bacteria adhering to HEp-2 cells revealed the presence of structures resembling BFP and rod-like fimbriae linking bacteria to bacteria and bacteria to the eukaryotic cell membrane. We suggest a role of these surface appendages in the interaction of EPEC with eukaryotic cells as well as in the overall pathogenesis of intestinal disease caused by EPEC.
Girón
J A
JA
Department of Microbiology and Immunology, Howard Hughes Medical Institute, Stanford University, California 94305.
Ho
A S
AS
Schoolnik
G K
GK
D000017:ABO Blood-Group System; D000595:Amino Acid Sequence; D001422:Bacterial Adhesion; D001425:Bacterial Outer Membrane Proteins / Q000032:analysis* / Q000302:isolation & purification; D015153:Blotting, Western; D003967:Diarrhea / Q000382:microbiology; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000472:pathogenicity / Q000502:physiology / Q000648:ultrastructure*; D016326:Extracellular Matrix Proteins / Q000494:pharmacology; D010861:Fimbriae, Bacterial / Q000648:ultrastructure*; D006384:Hemagglutination / Q000187:drug effects; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D007223:Infant; D046911:Macromolecular Substances; D008855:Microscopy, Electron, Scanning; D016253:Microscopy, Immunoelectron; D008969:Molecular Sequence Data; D014407:Tumor Cells, Cultured; D014552:Urinary Tract Infections / Q000382:microbiology
D000017:ABO Blood-Group System; D001425:Bacterial Outer Membrane Proteins; D016326:Extracellular Matrix Proteins; D046911:Macromolecular Substances