title: Production of shiga toxin by a luxS mutant of Escherichia coli O157:H7 in vivo and in vitro.
abstract: Quorum sensing is a type of bacterial communication mediated by chemical signaling molecules called autoinducers (AIs). The production of AI-2 and AI-3 is dependent on the luxS gene in Escherichia coli O157:H7. A luxS mutation caused a minimal decrease (about 2-fold) in Shiga toxin (Stx) production in in vitro cultures using Luria-Bertani broth. The effect of a luxS mutation on the virulence of E. coli O157:H7 was examined by using germfree mice. There were no differences between the luxS mutant and the wild-type in the bacterial counts in feces shedding, Stx production, or the survival of the mice. The treatment of ciprofloxacin decreased the bacteria in feces but increased the Stx production. However, even treatment with ciprofloxacin did not make any difference between the luxS mutant and the wild-type in animal experiments.
authors: Laboratory of Veterinary Public Health, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
authors: Byeonghwa
authors: B
authors: Jeon
authors: Kikuji
authors: K
authors: Itoh
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D013437:Carbon-Sulfur Lyases / Q000235:genetics / Q000502:physiology*; D002939:Ciprofloxacin / Q000494:pharmacology; D019453:Escherichia coli O157 / Q000187:drug effects / Q000378:metabolism* / Q000472:pathogenicity*; D005856:Germ-Free Life; D051379:Mice; D008807:Mice, Inbred BALB C; D009154:Mutation; D053038:Quorum Sensing; D022621:Shiga Toxin / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D002939:Ciprofloxacin; D022621:Shiga Toxin; D013437:Carbon-Sulfur Lyases; C117753:LuxS protein, Bacteria