产肠毒素大肠杆菌(enterotoxigenic Escherichia coli, ETEC)是一类引起断奶仔猪腹泻的重要病原菌,筛选获得高产抑制ETEC血凝性胞外多糖的芽孢杆菌可以有效预防这类动物疾病。该研究从健康动物粪便中分离获得芽孢杆菌,比较分析芽孢杆菌胞外多糖产量及其抑制ETEC血凝性的能力,最终筛选获得1株多糖产量大于20 g/L,多糖质量浓度在4 mg/mL时就能抑制ETEC血凝性的芽孢杆菌JN4。体外益生潜力评价发现,其芽孢生成率高,萌发率高,具有很好的耐受人工肠、胃液能力,对大部分常规抗生素敏感。通过生理生化及16 S rRNA序列分析,鉴定其为解淀粉芽孢杆菌JN4。
Enterotoxigenic Escherichia coli (ETEC) is a leading bacterial cause of diarrhea in weaned piglets. An effective prevention and treatement of ETEC caused diarrhea is to isolate a potential probiotic Bacillus strain which could produce exopolysaccharide (EPS) with anti-hemagglutination activity towards ETEC. Bacillus amyloliquefaciens JN4 was isolated from healthy piglets faeces. When cultured with LB medium containing 100 g/L sucrose, it could produce more than 20 g/L EPS. The EPS showed anti-hemagglutination activity with a titer of 4 mg/mL, lower than that of EPS from other Bacillus strains. The spores of JN4 were tolerant to gastric and small intestinal juice, indicated its capable to survive in the intestine, and the JN4 strain was sensitive to most commercial antibiotics.
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