School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore.
Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.
BMC Microbiol. 2024 Mar 28;24(1):104. doi: 10.1186/s12866-024-03263-y.
While particular strains within the Bacillus species, such as Bacillus subtilis, have been commercially utilised as probiotics, it is critical to implement screening assays and evaluate the safety to identify potential Bacillus probiotic strains before clinical trials. This is because some Bacillus species, including B. cereus and B. anthracis, can produce toxins that are harmful to humans.
In this study, we implemented a funnel-shaped approach to isolate and evaluate prospective probiotics from homogenised food waste - sesame oil meal (SOM). Of nine isolated strains with antipathogenic properties, B. subtilis SOM8 displayed the most promising activities against five listed human enteropathogens and was selected for further comprehensive assessment. B. subtilis SOM8 exhibited good tolerance when exposed to adverse stressors including acidity, bile salts, simulated gastric fluid (SGF), simulated intestinal fluid (SIF), and heat treatment. Additionally, B. subtilis SOM8 possesses host-associated benefits such as antioxidant and bile salt hydrolase (BSH) activity. Furthermore, B. subtilis SOM8 contains only haemolysin toxin genes but has been proved to display partial haemolysis in the test and low cytotoxicity in Caco-2 cell models for in vitro evaluation. Moreover, B. subtilis SOM8 intrinsically resists only streptomycin and lacks plasmids or other mobile genetic elements. Bioinformatic analyses also predicted B. subtilis SOM8 encodes various bioactives compound like fengycin and lichendicin that could enable further biomedical applications.
Our comprehensive evaluation revealed the substantial potential of B. subtilis SOM8 as a probiotic for targeting human enteropathogens, attributable to its exceptional performance across selection assays. Furthermore, our safety assessment, encompassing both phenotypic and genotypic analyses, showed B. subtilis SOM8 has a favourable preclinical safety profile, without significant threats to human health. Collectively, these findings highlight the promising prospects of B. subtilis SOM8 as a potent probiotic candidate for additional clinical development.
虽然芽孢杆菌属内的某些菌株，如枯草芽孢杆菌，已被商业化用作益生菌，但在进行临床试验之前，必须通过筛选试验并评估安全性来识别潜在的芽孢杆菌益生菌菌株。这是因为某些芽孢杆菌物种，包括蜡样芽孢杆菌和炭疽芽孢杆菌，会产生对人体有害的毒素。
在这项研究中，我们采用漏斗形方法从均质化食物废物-芝麻油渣（SOM）中分离和评估有前途的益生菌。在具有抗病原体特性的 9 个分离菌株中，枯草芽孢杆菌 SOM8 对 5 种列出的人类肠道病原体表现出最有希望的活性，因此被选为进一步的全面评估。枯草芽孢杆菌 SOM8 在暴露于酸、胆汁盐、模拟胃液（SGF）、模拟肠液（SIF）和热处理等不利应激源时表现出良好的耐受性。此外，枯草芽孢杆菌 SOM8 具有宿主相关的益处，如抗氧化和胆汁盐水解酶（BSH）活性。此外，枯草芽孢杆菌 SOM8 仅含有溶血素毒素基因，但已被证明在测试中表现出部分溶血和在体外评估的 Caco-2 细胞模型中低细胞毒性。此外，枯草芽孢杆菌 SOM8 天然仅抵抗链霉素，并且缺乏质粒或其他可移动遗传元件。生物信息学分析还预测枯草芽孢杆菌 SOM8 编码各种生物活性化合物，如丰原素和地衣素，这可能使其能够进一步用于生物医学应用。
我们的综合评估显示，枯草芽孢杆菌 SOM8 作为靶向人类肠道病原体的益生菌具有巨大潜力，这归因于其在选择试验中的卓越表现。此外，我们的安全性评估包括表型和基因型分析，表明枯草芽孢杆菌 SOM8 具有良好的临床前安全性特征，对人类健康没有重大威胁。总的来说，这些发现突显了枯草芽孢杆菌 SOM8 作为一种有前途的益生菌候选物用于进一步临床开发的前景。
