title: Yogurt containing bioactive molecules produced by Lactobacillus acidophilus La-5 exerts a protective effect against enterohemorrhagic Escherichia coli in mice.
abstract: An active fraction extracted from Lactobacillus acidophilus La5 cell-free spent medium (LAla-5AF) was incorporated in a dairy matrix and tested to assess its antivirulent effect against enterohemorrhagic Escherichia coli (EHEC). Mice in experimental groups were fed for  4 days with yogurt supplemented with LAla-5AF. On the fifth day, mice were challenged with a single dose (10(7) CFU per mouse) of E. coli O157:H7. The clinical manifestations of the infection were significantly less severe in mice fed the yogurt supplemented with LAla-5AF.  EHEC attachment and colonization was attenuated by LAla-5AF. Tumor necrosis factor alpha production was down-regulated, which might indicate a protective effect in the kidney during EHEC infection. To investigate the mechanisms associated with the in vivo effects observed, LAla-5AF was tested  by reverse transcription real-time PCR to confirm its effects on the expression of several virulence genes of EHEC O157. The results showed that these fractions were able to down-regulate several virulence genes of EHEC, including stxB2, qseA, luxS, tir, ler, eaeA, and hlyB.
authors.affiliation: Food Hygiene & Control Department, Faculty of Veterinary Medicine, Beni-Suef University, Egypt.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Zeinhom
authors.forename: Angela M
authors.initials: AM
authors.lastname: Tellez
authors.forename: Veronique
authors.initials: V
authors.lastname: Delcenserie
authors.forename: A M
authors.initials: AM
authors.lastname: El-Kholy
authors.forename: S H
authors.initials: SH
authors.lastname: El-Shinawy
authors.forename: Mansel W
authors.initials: MW
authors.lastname: Griffiths
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion / Q000502:physiology; D015169:Colony Count, Microbial; D015536:Down-Regulation; D019453:Escherichia coli O157 / Q000235:genetics / Q000254:growth & development*; D005260:Female; D007779:Lactobacillus acidophilus / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D019936:Probiotics; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D037521:Virulence Factors / Q000235:genetics*; D015014:Yogurt / Q000382:microbiology*
chemical_list: D014409:Tumor Necrosis Factor-alpha; D037521:Virulence Factors