Increasing multidrug-resistant pathogenic bacterial contamination in the environment has become the leading cause of food poisoning, resulting in life-threatening conditions due to late detection and limited therapeutic options. Escherichia coli O157:H7 is one such pathogen which is severely affecting the environmental livestock and ultimately leads to human infection. In this context, probiotics could be a useful strategy to minimize the growth of pathogens, as they produce several antimicrobial compounds and shows an exclusive competitive behavior against the pathogens. Therefore, supplementation of probiotics is wieldy accepted in the field of agriculture for the maintenance of animal’s health. Previously, we reported that W. confusa DD_A7 possesses anti-bacterial and immune-stimulatory activity in-vitro. Therefore, in the present study, we investigated the impact of oral-administration of DD_A7 powder against E. coli O157:H7. The 6 days post-fertilized zebrafish larvae were used to evaluate the pathogenicity of the microbe. 1 × 10⁸ CFU/ml of E. coli O157:H7 effectively induced the inflammatory response in zebrafish larvae. Where 1 × 10⁸ CFU/ml DD_A7 pre-treatment prolonged the survivability of zebrafish larvae and improved the immune response of zebrafish larvae against pathogenic infection. The antibacterial property of DD_A7 against the pathogen correlated with the significant reduction of oxidative stress and host inflammatory response, by inhibiting NF-κB and its downstream signaling pathway. The findings demonstrated the prophylactic activity of DD_A7 suggesting that its supplementation improved the host defense mechanism by reducing oxidative stress. The growth of pathogen was effectively suppressed in the DD_A7 pre-treated larvae and maintained a healthy gastrointestinal environment in the zebrafish model.

环境中多药耐药的致病细菌污染的增加已成为食物中毒的主要原因，由于检测迟到和治疗选择有限，导致了危及生命的状况。大肠杆菌O157：H7是一种严重影响环境牲畜并最终导致人类感染的病原体。在这种情况下，益生菌可能是减少病原体生长的有用策略，因为它们会产生几种抗菌化合物并显示出对病原体的排他性竞争行为。因此，益生菌补充剂在农业领域被广泛接受以维持动物的健康。先前，我们报道了W. confusaDD_A7具有体外抗菌和免疫刺激活性。因此，在本研究中，我们调查了口服DD_A7粉末对大肠杆菌O157：H7的影响。斑马鱼受精后6天的幼虫被用来评估微生物的致病性。1×10 ⁸ CFU / ml的大肠杆菌O157：H7可有效诱导斑马鱼幼虫的炎症反应。其中1×10 ⁸CFU / ml DD_A7预处理可延长斑马鱼幼虫的生存能力，并改善斑马鱼幼虫对病原体感染的免疫反应。DD_A7对病原体的抗菌性能与氧化应激的显着降低和宿主炎症反应的抑制作用有关，这是通过抑制NF-κB及其下游信号通路而实现的。该发现证明了DD_A7的预防活性，表明其补充通过降低氧化应激改善了宿主防御机制。在DD_A7预处理的幼虫中，病原体的生长得到了有效抑制，并且在斑马鱼模型中保持了健康的胃肠环境。