title: The inhibitory effect of colloidal bismuth hydroxide gel on Escherichia coli O157:H7 and on the activity of Shiga toxins.
abstract: BACKGROUND
  Shiga toxin-producing Escherichia coli (STEC) is the causative agent of hemolytic uremic syndrome (HUS). Colloidal bismuth hydroxide gel (CBHG) is an anti-diarrheal and antisecretory compound, which does not inhibit gastrointestinal motility and reaches an in vivo gut concentration of 10.8 mg/ml of bismuth. Its action on bacteria has not been studied. We analyzed its inhibitory effects on STEC, as well as the deactivation of the Shiga toxin (Stx) and its ability to block the spread of genes encoding Stx. We determined a minimum inhibitory concentration and bactericidal concentration for the STEC O157:H7 strain (EDL933), with CBHG and Chobet® bismuth cream with pectin (CBCHP). We analyzed its effect on Stx by means of cytotoxicity assay and ELISA, as well as its effect on the free 933 W Stx phage.
  
  
  RESULTS
  Effect on the EDL933 strain: CBHG: MIC 10 mg/ml of bismuth.
  MIC 6 mg/ml and MBC 15 mg/ml of bismuth. Effect on EDL933 virulence factors: significant decrease in active Stx and 933 W Stx phage titer. ELISA did not find significant differences with treatment.
  
  
  CONCLUSIONS
  The results obtained may be useful in the development of new therapeutic strategies based on the use of CBHG to prevent or improve the prognosis of HUS, as it can be used to control STEC infections.
authors.affiliation: Faculty of Biochemistry and Pharmaceutical Sciences, Department of Clinical Bacteriology, National University of Rosario, Suipacha 531, S2002LRK Rosario, Santa Fe, Argentina. tomassubils@hotmail.com.
authors.forename: Tomás
authors.initials: T
authors.lastname: Subils
authors.forename: Cecilia
authors.initials: C
authors.lastname: Casabonne
authors.forename: Claudia
authors.initials: C
authors.lastname: Balagué
mesh_terms: D001422:Bacterial Adhesion / Q000187:drug effects; D001729:Bismuth / Q000494:pharmacology*; D003102:Colloids; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000235:genetics; D005782:Gels; D005798:Genes, Bacterial; D006878:Hydroxides / Q000494:pharmacology*; D007124:Immunoenzyme Techniques; D008826:Microbial Sensitivity Tests; D022603:Shiga Toxins / Q000037:antagonists & inhibitors*
chemical_list: D003102:Colloids; D005782:Gels; D006878:Hydroxides; D022603:Shiga Toxins; D001729:Bismuth