A plasmid-encoded surface protein on Enterococcus faecalis augments its internalization by cultured intestinal epithelial cells.
Aggregation substance, a plasmid-encoded Enterococcus faecalis surface protein, plays a role in mediating the formation of mating aggregates, resulting in plasmid transfer. The role of aggregation substance in the internalization of E. faecalis by cultured intestinal epithelial cells, namely HT-29 cells, was analyzed. It was associated with a significant increase in endocytosis of E. faecalis by HT-29 cells: Numbers of internalized enterococci were fewer than of an invasive strain of Listeria monocytogenes, similar to Salmonella typhimurium and another L. monocytogenes strain, and greater than relatively noninvasive strains of E. faecalis, Proteus mirabilis, and Escherichia coli. Electron microscopy confirmed aggregation substance on the surface of strains interacting with the enterocyte microvillous surface, and intracellular enterococci were localized within membrane-bound vacuoles in the enterocyte cytoplasm. Thus, aggregation substance may facilitate E. faecalis internalization by host epithelial cells.
Olmsted
S B
SB
Department of Laboratory Medicine, University of Minnesota, Minneapolis 55455.
Dunny
G M
GM
Erlandsen
S L
SL
Wells
C L
CL
D001422:Bacterial Adhesion; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D004705:Endocytosis / Q000502:physiology*; D004755:Enterobacteriaceae / Q000502:physiology; D013293:Enterococcus faecalis / Q000472:pathogenicity* / Q000502:physiology / Q000648:ultrastructure; D004847:Epithelial Cells; D004848:Epithelium / Q000382:microbiology; D006801:Humans; D007413:Intestinal Mucosa / Q000166:cytology / Q000382:microbiology* / Q000648:ultrastructure; D008089:Listeria monocytogenes / Q000502:physiology; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D008871:Microvilli / Q000382:microbiology / Q000648:ultrastructure; D010957:Plasmids; D014407:Tumor Cells, Cultured
D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D008565:Membrane Proteins; C083493:Sec10 protein, Enterococcus faecalis; C071729:Asc10 protein, Enterococcus faecalis