Abstract—Bacillus cereus is a spore-forming bacterium found in the environment mainly in soil. Bacillus spores are known to be extremely resistant not only to environmental factors, but also to various sanitation regimes. This leads to spore contamination of toxin-producing strains in hospital and food equipment and, therefore, poses a great threat to human health. Two clinical isolates identified as B. cereus and B. cytotoxicus were used in the present work. It was shown that their calcium ion content was significantly lower than that of the reference strains. According to electron microscopy, one of the SRCC 19/16 isolates has an enlarged exosporium, and the SRCC 1208 isolate has large electron-dense inclusions of an unclear nature during sporulation. We can assume that these contain a biologically active component with a cytotoxic effect and possibly play a role in pathogenesis. Comparative chemical, biochemical, physiological, and ultrastructural analysis of spores of clinical isolates and reference strains of B. cereus was performed. The results we obtained deepen our understanding of the properties of spores that contribute to the increased pathogenicity of B. cereus group species.

摘要：蜡样芽孢杆菌是一种产芽孢细菌，主要存在于土壤中。众所周知，芽孢杆菌孢子不仅对环境因素具有极强的抵抗力，而且对各种卫生制度也具有极强的抵抗力。这导致医院和食品设备中产毒菌株的孢子污染，从而对人类健康构成巨大威胁。两种临床分离株被鉴定为蜡状芽孢杆菌和细胞毒性芽孢杆菌目前的工作中使用了。结果表明，其钙离子含量显着低于参考菌株。根据电子显微镜观察，其中一个 SRCC 19/16 分离株具有增大的孢子外膜，而 SRCC 1208 分离株在孢子形成过程中具有性质不清楚的大电子致密内含物。我们可以假设它们含有具有细胞毒性作用的生物活性成分，并可能在发病机制中发挥作用。对蜡样芽胞杆菌临床分离株和参考菌株的孢子进行了化学、生化、生理和超微结构的比较分析。我们获得的结果加深​​了我们对孢子特性的理解，这些特性有助于蜡样芽孢杆菌组物种致病性的增加。