Inhibitory effect of various lactobacilli against pathogenic strains of E. coli in model system Caco2 cells was determined by enumerating the number of adhering E. coli after pre-incubation (exclusion), post-incubation (displacement) or co-incubation (competition) with lactobacilli. Porcine E. coli strain F107 (F18ab, Stx2v) in the competition assay with porcine lactobacillus strain P10 gave bacterial counts 7.25 (log CFU per well); in the exclusion test it was only 7.05 while in displacement test it reached 7.29. The lowest E. coli counts adhering to Caco-2 cells were in exclusion assay (pre-incubation, Lactobacillus inoculated as the first). Pre-treatment of E. coli with our lactobacilli strains reduced the cultivable E. coli numbers.

• MeSH
• Bacterial Adhesion physiology   MeSH
• Caco-2 Cells MeSH
• Escherichia coli physiology   MeSH
• Lactobacillus metabolism   MeSH
• Humans MeSH
• Colony Count, Microbial MeSH
• Swine microbiology   MeSH
• Probiotics pharmacology   MeSH
• Intestinal Mucosa microbiology   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

One hundred and four enterotoxin producing Escherichia coli strains of wide geographical origin were tested for the expression of curli fimbriae by transmission electronmicroscopy and by ELISA using curli-specific antibodies, as well as for the presence of curli-specific gene sequences by PCR. All isolates, irrespective of the production of the fimbriae, carried sequences specific for the structure (csgA) and for one of the regulator genes (crl) of curli expression, respectively. Curli fimbriae were detected in 56 strains (53.8 %). Thirty-six strains expressed curli only when growing at 30 degrees C, 4 isolates were weakly curliated at 37 degrees C only, while on 16 strains curli was observed at both temperatures. On isolates carrying curli at both temperatures the expression of the fimbria was significantly stronger at 30 degrees C than at 37 degrees C. Curli proficiency significantly, but not completely, correlated with the binding of the Congo Red dye. The expression of curli did not confer epithelial cell invasiveness to ETEC strains but, once expressed at 30 degrees C, it facilitated the adherence of the bacteria to plastic surfaces. Curli present in more than half of the ETEC strains and expressed preferentially at low temperatures could be a factor facilitating the environmental survival of this food- and water-borne pathogen.

• MeSH
• Bacterial Adhesion MeSH
• Fimbriae, Bacterial * ultrastructure   MeSH
• Genes, Bacterial MeSH
• Bacterial Proteins analysis   MeSH
• Enzyme-Linked Immunosorbent Assay MeSH
• Enterotoxins biosynthesis   MeSH
• Escherichia coli genetics   isolation & purification   ultrastructure   MeSH
• Congo Red metabolism   MeSH
• Escherichia coli Proteins chemistry   genetics   immunology   MeSH
• Gene Expression Regulation, Bacterial MeSH
• Genes, Regulator MeSH
• Temperature MeSH
• Microscopy, Electron, Transmission MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Bacterial Proteins MeSH
• Crl protein, Bacteria MeSH Browser
• csgA protein, E coli MeSH Browser
• Enterotoxins MeSH
• Congo Red MeSH
• Escherichia coli Proteins MeSH