Laboratory of Food Microbiology and Food Preservation (member of Food2Know), Department of Food Safety and Food Quality, Faculty of Bioscience Engineering, Ghent University, Belgium; Department of Food Safety and Food Quality Management, University of Belgrade - Faculty of Agriculture, Serbia.
Int J Food Microbiol. 2013 Oct 15;167(2):236-43. doi: 10.1016/j.ijfoodmicro.2013.09.001. Epub 2013 Sep 24.
The potential of Bacillus cereus to cause a diarrheal toxico-infection is related to its ability to perform de novo enterotoxin production in the small intestine. A prerequisite for this is presence of sufficient numbers of B. cereus that have survived gastro-intestinal passage. It is known that the percentage of survival is much smaller for vegetative cells in comparison to spores and it is therefore important to know the state in which B. cereus is ingested. The results of the current study performed on twelve B. cereus strains, comprising both diarrheal and emetic type, indicate that exposure via contaminated foods mainly concerns vegetative cells. Inoculated vegetative cells grew to high counts, with the growth dynamic depending on the storage temperature. At 28 °C growth to high counts resulted in spore formation, in general, after 1 day of storage. One strain was an exception, producing spores only after 16 days. At 12 °C obtained high counts did not result in spore formation for 11 of 12 tested strains after two weeks of storage. The highest counts and time to sporulation were different between strains, but no difference was observed on the group level of diarrheal and emetic strains. The spore counts were always lower than vegetative cell counts and occurred only when food was obviously sensory spoiled (visual and odor evaluation). Similar observations were made with food inoculated with B. cereus spores instead of vegetative cells. Although the prospect of consuming spores was found very weak, the numbers of vegetative B. cereus cells were high enough, without obvious sensory deviation, to survive in sufficient level to cause diarrheal toxico-infection.
蜡样芽胞杆菌引起腹泻性中毒感染的潜力与其在小肠中进行从头肠毒素生产的能力有关。这一前提是有足够数量的蜡样芽胞杆菌存活下来并通过了胃肠道。已知与孢子相比，营养细胞的存活率要小得多，因此了解蜡样芽胞杆菌的摄入状态非常重要。对 12 株蜡样芽胞杆菌（包括腹泻型和呕吐型）进行的当前研究结果表明，通过污染食物暴露主要涉及营养细胞。接种的营养细胞大量生长，其生长动态取决于储存温度。在 28°C 下，储存 1 天后，通常会因生长而形成孢子。一株菌是个例外，仅在 16 天后才产生孢子。在 12°C 下，在 11 株测试菌株中，有 11 株在储存两周后不会因获得高计数而形成孢子。在菌株之间，最高计数和形成孢子的时间存在差异，但在腹泻型和呕吐型菌株的组水平上没有观察到差异。孢子计数始终低于营养细胞计数，并且仅在食物明显感官变质（视觉和气味评估）时才会发生。用蜡样芽胞杆菌孢子而不是营养细胞接种食物也观察到了类似的结果。虽然摄入孢子的可能性被认为非常微弱，但足够数量的蜡样芽胞杆菌营养细胞在没有明显感官偏差的情况下存活下来，足以引起腹泻性中毒感染。
