The Bacillus cereus Food Infection as Multifactorial Process

Abstract

The ubiquitous soil bacterium Bacillus cereus presents major challenges to food safety. It is responsible for two types of food poisoning, the emetic form due to food intoxication and the diarrheal form emerging from food infections with enteropathogenic strains, also known as toxico-infections, which are the subject of this review. The diarrheal type of food poisoning emerges after production of enterotoxins by viable bacteria in the human intestine. Basically, the manifestation of the disease is, however, the result of a multifactorial process, including B. cereus prevalence and survival in different foods, survival of the stomach passage, spore germination, motility, adhesion, and finally enterotoxin production in the intestine. Moreover, all of these processes are influenced by the consumed foodstuffs as well as the intestinal microbiota which have, therefore, to be considered for a reliable prediction of the hazardous potential of contaminated foods. Current knowledge regarding these single aspects is summarized in this review aiming for risk-oriented diagnostics for enteropathogenic B. cereus.

The Food Poisoning Toxins of Bacillus cereus

“…Lately, both syndromes have been reported from all over the world. Basically, emetic strains are found less frequently in foods as well as in the environment than enteropathogenic strains [ 27 , 36 , 37 ]. In a multitude of studies, new isolates were screened for the presence of the toxin genes nhe (ABC) , hbl (CDAB) , cytK (1,2) , entFM , and ces .…”

“…Multiple attempts have been made to predict the toxic potential of newly isolated B. cereus strains [ 27 , 297 ]. This is a difficult venture, as factors such as toxin gene expression, secretion and protein stability are highly diverse among members of the PlcR regulon within one single strain [ 298 ].…”

“…This means that it is hard to predict if a certain isolate is capable of causing an infection once consumed, especially as only enterotoxins produced by viable B. cereus in the intestine contribute to the diarrheal disease. Thus, many additional factors regarding the host have to be taken into account, which we recently investigated and summarized [ 27 , 92 , 278 , 297 ].…”

“…The second, diarrheal form of food poisoning is also associated with a variety of different foodstuffs [ 27 ]. This form of disease manifests mainly in diarrhea and abdominal cramps, similar to food poisoning by Clostridium perfringens type A [ 5 ].…”

“…A food infection with enteropathogenic B. cereus can be seen as a multifactorial process, as a number of individual steps have to be considered before the onset of the disease, including prevalence and survival of B. cereus in different foodstuffs, survival of the stomach passage, germination of spores, active movement towards and adhesion to the intestinal epithelium, enterotoxin production under intestinal conditions, as well as the influence of consumed foods and the intestinal microbiota on these processes. We recently summarized these steps in a separate review [ 27 ]. Nevertheless, production and action of the enterotoxins are of the upmost relevance for the course of the diarrheal disease.…”