title: The LT1 and LT2 variants of the enterotoxigenic Escherichia coli (ETEC) heat-labile toxin (LT) are associated with major ETEC lineages.
abstract: The heat-labile toxin (LT) is one of the major virulence factors of enterotoxigenic Escherichia coli (ETEC). We recently described that 20 polymorphic LT variants are present in ETEC strains isolated globally. Two of the variants, LT1 and LT2, are particularly common and we found that they were associated with clonal ETEC lineages that express the colonization factors (CFs), CFA/I, CS1+CS3, CS2+CS3, and CS5+CS6. ETEC expressing these CFs are frequently found among ETEC strains isolated from cases with diarrhea. ETEC expressing the colonization factors CS1+CS3, and CS2+CS3 are found in 2 discrete clonal lineages and express the LT1 variant and heat stable toxin (STh). Although they clearly are virulent they neither produce, nor secrete, high amounts of LT toxin. On the other hand ETEC strains expressing LT, STh, CFA/I and LT, STh, CS5+CS6, carry the LT2 variant and produce and secrete significantly more LT toxin. Despite differences in toxin production, LT1 and LT2 are found in ETEC lineages that have managed to spread globally confirming that these variants are important for ETEC virulence.
authors.affiliation: a Department of Microbiology and Immunology ; Sahlgrenska Academy; University of Gothenburg ; Göteborg , Sweden.|b Institute of Molecular Biology and Biotechnology; Universidad Mayor de San Andrés ; La Paz , Bolivia.|c Department of Microbiology ; Tumor and Cell Biology; Karolinska Institutet ; Stockholm , Sweden.
authors.forename: Enrique
authors.initials: E
authors.lastname: Joffré
authors.affiliation: c Department of Microbiology ; Tumor and Cell Biology; Karolinska Institutet ; Stockholm , Sweden.
authors.forename: Åsa
authors.initials: Å
authors.lastname: Sjöling
mesh_terms: D001427:Bacterial Toxins / Q000235:genetics* / Q000378:metabolism*; D054307:Enterotoxigenic Escherichia coli / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D004768:Enterotoxins / Q000235:genetics* / Q000378:metabolism*; D004927:Escherichia coli Infections / Q000382:microbiology / Q000473:pathology*; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism*; D010861:Fimbriae, Bacterial / Q000235:genetics*; D005759:Gastroenteritis / Q000382:microbiology / Q000473:pathology*; D006801:Humans
chemical_list: D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; C027538:heat-labile enterotoxin, E coli
keywords: ETEC; Heat labile toxin; LT1; LT2; gene expression; lineages; variants