title: The effect of selected factors on the survival of Bacillus cereus in the human gastrointestinal tract.
abstract: Bacillus cereus is a Gram-positive bacterium widely distributed in soil and vegetation. This bacterial species can also contaminate raw or processed foods. Pathogenic B. cereus strains can cause a range of infections in humans, as well as food poisoning of an emetic (intoxication) or diarrheal type (toxico-infection). Toxico-infections are due to the action of the Hbl toxin, Nhe toxin, and cytotoxin K produced by the microorganism in the gastrointestinal tract. This occurs once the spores or vegetative B. cereus cells survive the pH barrier of the stomach and reach the small intestine where they produce toxins in sufficient amounts. This article discusses the effect of various factors on the survival of B. cereus in the gastrointestinal tract, including low pH and the presence of digestive enzymes in the stomach, bile salts in the small intestine, and indigenous microflora in the lower parts of the gastrointestinal tract. Additional aspects also reported to affect B. cereus survival and virulence in the gastrointestinal tract include the interaction of the spores and vegetative cells with enterocytes. In vitro studies revealed that both vegetative B. cereus and spores can survive in the gastrointestinal tract suggesting that the biological form of the microorganism may have less influence on the occurrence of the symptoms of infection than was once believed. It is most likely the interaction between the pathogen and enterocytes that is necessary for the diarrheal form of B. cereus food poisoning to develop. The adhesion of B. cereus to the intestinal epithelium allows the bacterium to grow and produce enterotoxins in the proximity of the epithelium. Recent studies suggest that the human intestinal microbiota inhibits the growth of vegetative B. cereus cells considerably.
authors: Division of Milk Biotechnology, Department of Biotechnology, Microbiology and Food Evaluation, Faculty of Food Sciences, Warsaw University of Life Sciences - SGGW, Nowoursynowska 159C St, 02-787 Warsaw, Poland. Electronic address: anna_berthold@sggw.pl.
authors: Anna
authors: A
authors: Berthold-Pluta
authors: Division of Milk Biotechnology, Department of Biotechnology, Microbiology and Food Evaluation, Faculty of Food Sciences, Warsaw University of Life Sciences - SGGW, Nowoursynowska 159C St, 02-787 Warsaw, Poland.
authors: Antoni
authors: A
authors: Pluta
authors: Prof. Wacław Dąbrowski Institute of Agricultural and Food Biotechnology, Inter-Department Problem Group for Dairy Industries, Rakowiecka St 36, 02-532 Warsaw, Poland.
authors: Monika
authors: M
authors: Garbowska
mesh_terms: D001409:Bacillus cereus / Q000187:drug effects* / Q000502:physiology*; D001422:Bacterial Adhesion; D001427:Bacterial Toxins / Q000378:metabolism; D001647:Bile Acids and Salts / Q000378:metabolism; D020895:Enterocytes / Q000382:microbiology; D004798:Enzymes / Q000378:metabolism; D041981:Gastrointestinal Tract / Q000382:microbiology*; D054884:Host-Pathogen Interactions; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007413:Intestinal Mucosa / Q000382:microbiology; D056265:Microbial Interactions; D050296:Microbial Viability / Q000187:drug effects*; D064307:Microbiota
chemical_list: D001427:Bacterial Toxins; D001647:Bile Acids and Salts; D004798:Enzymes
keywords: Bacillus cereus; Pathogenesis; Simulated gastrointestinal conditions