Bacillus cereus NVH 0500/00 Can Adhere to Mucin but Cannot Produce Enterotoxins during Gastrointestinal Simulation.
Adhesion to the intestinal epithelium could constitute an essential mechanism of Bacillus cereus pathogenesis. However, the enterocytes are protected by mucus, a secretion composed mainly of mucin glycoproteins. These may serve as nutrients and sites of adhesion for intestinal bacteria. In this study, the food poisoning bacterium B. cereus NVH 0500/00 was exposed in vitro to gastrointestinal hurdles prior to evaluation of its attachment to mucin microcosms and its ability to produce nonhemolytic enterotoxin (Nhe). The persistence of mucin-adherent B. cereus after simulated gut emptying was determined using a mucin adhesion assay. The stability of Nhe toward bile and pancreatin (intestinal components) in the presence of mucin agar was also investigated. B. cereus could grow and simultaneously adhere to mucin during in vitro ileal incubation, despite the adverse effect of prior exposure to a low pH or intestinal components. The final concentration of B. cereus in the simulated lumen at 8 h of incubation was 6.62 ± 0.87 log CFU ml(-1). At that point, the percentage of adhesion was approximately 6%. No enterotoxin was detected in the ileum, due to either insufficient bacterial concentrations or Nhe degradation. Nevertheless, mucin appears to retain B. cereus and to supply it to the small intestine after simulated gut emptying. Additionally, mucin may play a role in the protection of enterotoxins from degradation by intestinal components.
Laboratory of Microbial Ecology and Technology (LabMET), Department of Biochemical and Microbial Technology, Ghent University, Ghent, Belgium Laboratory of Food Microbiology and Food Preservation (LFMFP), Department of Food Safety and Food Quality, Ghent University, Ghent, Belgium.
Varvara
V
Tsilia
Laboratory of Microbial Ecology and Technology (LabMET), Department of Biochemical and Microbial Technology, Ghent University, Ghent, Belgium.
Frederiek-Maarten
FM
Kerckhof
Laboratory of Food Microbiology and Food Preservation (LFMFP), Department of Food Safety and Food Quality, Ghent University, Ghent, Belgium.
Andreja
http://orcid.org/0000-0003-1062-0564
A
Rajkovic
Technology and Food Science Unit, Institute for Agricultural and Fisheries Research (ILVO), Melle, Belgium Department of Pathology, Bacteriology and Poultry Diseases, Ghent University, Merelbeke, Belgium.
Marc
M
Heyndrickx
Laboratory of Microbial Ecology and Technology (LabMET), Department of Biochemical and Microbial Technology, Ghent University, Ghent, Belgium tom.vandewiele@ugent.be.
Tom
T
Van de Wiele
D001409:Bacillus cereus / Q000254:growth & development / Q000502:physiology*; D001422:Bacterial Adhesion; D015169:Colony Count, Microbial; D020895:Enterocytes / Q000382:microbiology; D004768:Enterotoxins / Q000378:metabolism; D005746:Gastric Emptying; D007082:Ileum / Q000382:microbiology; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000382:microbiology*; D009077:Mucins / Q000502:physiology*
D004768:Enterotoxins; D009077:Mucins; C040792:enterotoxin, Bacillus cereus