Faculty of Bioscience Engineering, Department of Food Safety and Quality, Laboratory of Food Microbiology and Food Preservation (LFMFP), Ghent University, Ghent, Belgium.
J Food Prot. 2012 Apr;75(4):690-4. doi: 10.4315/0362-028X.JFP-11-481.
The enteric pathogen Bacillus cereus must survive gastric passage in order to cause diarrhea by enterotoxin production in the small intestine. The acid resistance and the survival after gastric passage were assessed by in vitro experiments with acidified growth medium and gastric simulation medium with B. cereus NVH 1230-88 vegetative cells and spores. First, batch incubations at constant pH values for 4 h, which represented different physiological states of the stomach, showed that spores were resistant to any gastric condition in the pH range of 2.0 to 5.0, while vegetative cells were rapidly inactivated at pH values of ≤4.0. Second, a dynamic in vitro gastric experiment was conducted that simulated the continuously changing in vivo conditions due to digestion dynamics by gradually decreasing the pH from 5.0 to 2.0 and fractional emptying of the stomach 30 to 180 min from the start of the experiment. All of the B. cereus spores and 14% (± 9%) of the vegetative cells survived the dynamic simulation of gastric passage.
肠病原体蜡样芽孢杆菌必须在胃酸中存活才能通过小肠产生肠毒素引起腹泻。采用酸化生长培养基和胃模拟培养基，对蜡样芽孢杆菌 NVH 1230-88 营养细胞和孢子进行体外实验，评估其耐酸性和胃内生存能力。首先，在恒定 pH 值下进行 4 h 的分批孵育，代表胃的不同生理状态，结果表明，孢子在 pH 值 2.0 到 5.0 范围内可耐受任何胃内条件，而营养细胞在 pH 值≤4.0 时迅速失活。其次，进行了动态体外胃实验，通过逐渐降低 pH 值从 5.0 到 2.0 并在实验开始后 30 至 180 分钟进行胃排空分数，模拟因消化动力学而不断变化的体内条件。所有蜡样芽孢杆菌孢子和 14%（±9%）的营养细胞都能在胃内模拟传代中存活。
