title: Inhibition of Escherichia coli O157:H7 motility and biofilm by β-sitosterol glucoside.
abstract: BACKGROUND
  Escherichia coli O157:H7 (EHEC) is a food borne pathogen, which causes diarrhea and hemolytic uremic syndrome (HUS). There is an urgent need of novel antimicrobials for treatment of EHEC as conventional antibiotics enhance shiga toxin production and potentiate morbidity and mortality.
  
  
  METHODS
  Six bioactive compounds were isolated, identified from citrus and evaluated for the effect on EHEC biofilm and motility. To determine the possible mode of action, a series of genes known to affect biofilm and motility were overexpressed and the effect on biofilm/motility was assessed. Furthermore, the relative expression of genes involved in motility and biofilm formation was measured by qRT-PCR in presence and absence of phytochemicals, to examine the repression caused by test compounds.
  
  
  RESULTS
  The β-sitosterol glucoside (SG) was identified as the most potent inhibitor of EHEC biofilm formation and motility without affecting the cell viability. Furthermore, SG appears to inhibit the biofilm and motility through rssAB and hns mediated repression of flagellar master operon flhDC.
  
  
  CONCLUSIONS
  SG may serve as novel lead compound for further development of anti-virulence drugs.
  
  
  CONCLUSIONS
  Plant sterols constitute significant part of diet and impart various health benefits. Here we present the first evidence that SG, a plant sterol has significant effect on EHEC motility, a critical virulence factor, and may have potential application as antivirulence strategy.
authors.affiliation: Vegetable and Fruit Improvement Center, Department of Horticultural Sciences, Texas A&M University, College Station, TX 77843, USA.
authors.forename: Amit
authors.initials: A
authors.lastname: Vikram
authors.forename: G K
authors.initials: GK
authors.lastname: Jayaprakasha
authors.forename: Ram M
authors.initials: RM
authors.lastname: Uckoo
authors.forename: Bhimanagouda S
authors.initials: BS
authors.lastname: Patil
mesh_terms: D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D012855:Sitosterols / Q000494:pharmacology*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D012855:Sitosterols; D015534:Trans-Activators; D014157:Transcription Factors; D037521:Virulence Factors; C090552:flhC protein, E coli; C090553:flhD protein, E coli; C098923:rssB protein, E coli; C011015:lyoniside
keywords: Anti-virulence; Citrus; Flagella; Hns; Phytosterol; Polymethoxyflavones; RssAB