title: Bifidobacterium spp. influences the production of autoinducer-2 and biofilm formation by Escherichia coli O157:H7.
abstract: The effect of Bifidobacterium spp. on the production of quorum-sensing (QS) signals and biofilm formation by enterohemorrhagic Escherichia coli (EHEC) O157:H7 was investigated. In an AI-2 bioassay, cell extracts of Bifidobacterium longum ATCC 15707 resulted in a 98-fold reduction in AI-2 activity in EHEC O157:H7 as well as in the Vibrio harveyi reporter strain, even though they did not inhibit the growth of EHEC O157:H7. In addition, they resulted in a 36% reduction in biofilm formation by the organism. Consistently, the virulence of EHEC O157:H7 was significantly attenuated by the presence of cell extracts of B. longum ATCC 15707 in the Caenorhabditis elegans nematode in vivo model. By a proteome analysis using two dimensional electrophoresis (2-DE), we determined that seven proteins including formation of iron-sulfur protein (NifU), thiol:disulfide interchange protein (DsbA), and flagellar P-ring protein (FlgI) were differentially regulated in the EHEC O157:H7 when supplemented with cell extracts of B. longum ATCC 15707. Taken together, these findings propose a novel function of a dairy adjunct in repressing the virulence of EHEC O157:H7.
authors.affiliation: Department of Animal Science, Institute of Rare Earth for Biological Application, Chonbuk National University, Jeonju 561-756, Republic of Korea.
authors.forename: Younghoon
authors.initials: Y
authors.lastname: Kim
authors.forename: Jae Won
authors.initials: JW
authors.lastname: Lee
authors.forename: Seo-Gu
authors.initials: SG
authors.lastname: Kang
authors.forename: Sejong
authors.initials: S
authors.lastname: Oh
authors.forename: Mansel W
authors.initials: MW
authors.lastname: Griffiths
mesh_terms: D000328:Adult; D000818:Animals; D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology*; D001644:Bifidobacterium / Q000737:chemistry*; D018441:Biofilms / Q000254:growth & development*; D017173:Caenorhabditis elegans / Q000382:microbiology; D004195:Disease Models, Animal; D004927:Escherichia coli Infections / Q000382:microbiology; D019453:Escherichia coli O157 / Q000737:chemistry / Q000187:drug effects* / Q000472:pathogenicity / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000032:analysis; D006714:Homoserine / Q000031:analogs & derivatives* / Q000378:metabolism; D006801:Humans; D007223:Infant; D007783:Lactones / Q000378:metabolism*; D056265:Microbial Interactions; D020543:Proteome / Q000032:analysis; D016019:Survival Analysis; D014733:Vibrio / Q000254:growth & development / Q000378:metabolism / Q000502:physiology
chemical_list: D000900:Anti-Bacterial Agents; D029968:Escherichia coli Proteins; D007783:Lactones; C091088:N-octanoylhomoserine lactone; D020543:Proteome; D006714:Homoserine