Berthold-Pluta Anna, Pluta Antoni, Garbowska Monika
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.
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.
Microb Pathog. 2015 May;82:7-14. doi: 10.1016/j.micpath.2015.03.015. Epub 2015 Mar 17.
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.
蜡样芽孢杆菌是一种革兰氏阳性菌，广泛分布于土壤和植被中。该细菌物种也可污染生的或加工过的食品。致病性蜡样芽孢杆菌菌株可导致人类发生一系列感染，以及引起呕吐型（中毒）或腹泻型（毒素感染）食物中毒。毒素感染是由于该微生物在胃肠道中产生的Hbl毒素、Nhe毒素和细胞毒素K的作用。一旦芽孢或蜡样芽孢杆菌的营养细胞在胃的pH屏障中存活下来并到达小肠，在那里它们产生足够量的毒素，就会发生这种情况。本文讨论了各种因素对蜡样芽孢杆菌在胃肠道中存活的影响，包括胃中的低pH值和消化酶的存在、小肠中的胆汁盐以及胃肠道下部的本土微生物群。据报道，其他影响蜡样芽孢杆菌在胃肠道中存活和毒力的方面还包括芽孢和营养细胞与肠上皮细胞的相互作用。体外研究表明，蜡样芽孢杆菌的营养细胞和芽孢都能在胃肠道中存活，这表明微生物的生物学形态对感染症状发生的影响可能比以往认为的要小。蜡样芽孢杆菌食物中毒腹泻型的发生很可能需要病原体与肠上皮细胞之间的相互作用。蜡样芽孢杆菌与肠上皮的粘附使细菌能够在上皮附近生长并产生肠毒素。最近的研究表明，人类肠道微生物群会显著抑制蜡样芽孢杆菌营养细胞的生长。
