title: Evaluation of in vitro properties of di-tri-octahedral smectite on clostridial toxins and growth.
abstract: BACKGROUND
  Clostridial colitis and endotoxaemia of intestinal origin are significant causes of morbidity and mortality in horses. Intestinal adsorbents are available for treatment of these conditions; however, little information exists supporting their use.
  
  
  OBJECTIVE
  To evaluate the ability of di-tri-octahedral smectite to bind to Clostridium difficile toxins A and B, C. perfringens enterotoxin and endotoxin, inhibit clostridial growth and the actions of metronidazole in vitro.
  
  
  METHODS
  Clostridium difficile toxins, C. perfringens enterotoxin and endotoxin were mixed with serial dilutions of di-tri-octahedral smectite, then tested for the presence of clostridial toxins or endotoxin using commercial tests. Serial dilutions of smectite were tested for the ability to inhibit growth of C. perfringens in culture broth, and to interfere with the effect of metronidazole on growth of C. perfringens in culture broth.
  
  
  RESULTS
  Clostridium difficile toxins A and B, and C. perfringens enterotoxin were completely bound at dilutions of 1:2 to 1:16. Partial binding of C. difficile toxins occurred at dilutions up to 1:256 while partial binding of C. perfringens enterotoxin occurred up to a dilution of 1:128. Greater than 99% binding of endotoxin occurred with dilutions 1:2 to 1:32. No inhibition of growth of C. difficile or C. perfringens was present at any dilution, and there was no effect on the action of metronidazole.
  
  
  CONCLUSIONS
  Di-tri-octahedral smectite possesses the ability to bind C. difficile toxins A and B, C. perfringens enterotoxin and endotoxin in vivo while having no effect on bacterial growth or the action of metronidazole.
  
  
  CONCLUSIONS
  In vivo studies are required to determine whether di-tri-octahedral smectite might be a useful adjunctive treatment of clostridial colitis and endotoxaemia in horses.
authors.affiliation: Ontario Veterinary College, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
authors.forename: J S
authors.initials: JS
authors.lastname: Weese
authors.forename: N M
authors.initials: NM
authors.lastname: Cote
authors.forename: R V G
authors.initials: RV
authors.lastname: deGannes
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000037:antagonists & inhibitors / Q000494:pharmacology; D001426:Bacterial Proteins; D001427:Bacterial Toxins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D016360:Clostridioides difficile / Q000378:metabolism; D003016:Clostridium perfringens / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004760:Enterocolitis / Q000188:drug therapy / Q000662:veterinary; D004768:Enterotoxins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D005765:Gastrointestinal Agents / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use; D006734:Horse Diseases / Q000188:drug therapy; D006736:Horses; D008795:Metronidazole / Q000037:antagonists & inhibitors / Q000494:pharmacology; D017640:Silicates
chemical_list: D000890:Anti-Infective Agents; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004768:Enterotoxins; D005765:Gastrointestinal Agents; D017640:Silicates; C035598:enterotoxin, Clostridium; C041348:tcdA protein, Clostridium difficile; C031815:toxB protein, Clostridium difficile; D008795:Metronidazole; C033214:Smectite