乳酸杆菌对攻毒小鼠的保护作用和对肠道菌群的影响

The Antagonism of Lactobacillus casei Zhang to Pathogenic Escherichia coli in Mice and the Influence on the Microbial Population in Gut

将含有乳酸杆菌Lactobacillus casei Zhang的悬浮液分组饲喂小鼠,然后分别用E.coliO157和K88攻毒观察发病情况。攻毒4d后取对照组和喂菌组未死亡小鼠的肠内容物,用选择性培养基分离纯化大肠杆菌和乳酸菌,提取分离到菌株的总DNA,进行ERIC-PCR扩增分析。发现灌服L.casei Zhang可以降低攻毒后小鼠的死亡率,在停止饲喂乳酸菌的第4d从小鼠肠道内分离到L.casei Zhang,从饲喂组未分离到E.coliO157和K88,喂L.casei Zhang使小鼠肠道中大肠杆菌总数极显著低于对照组。表明所饲喂的乳杆菌可以在小鼠肠道内定殖并对小鼠起到保护作用。

L. casei Zhang soliquoid were fed to mice, after the mice were counteracted toxic E. coli 0157 and k88, we observed the incidence of mice. We obtained the intestinal contents of mice in control groups and feeding oral lactobacilli groups which were live at the fourth day after they were counteracted toxic Escherichia coli 0157 and K88, E. coli and Lactobacillus which were in intestinal contents were isolated and purified by selective medium, and the total DNA of isolated bacterium was extracted, then amplified by ERIC-PCR. We found that Feeden by L. casei Zhang can reduce the death rate of mice which were counteracted toxic E. coli0157 and k88. After stop feeding lactobacilli at the fourth day, L. casei Zhang was isolated from intestinal tract of mice, But E. coli0157 and k88 wasn＇ t isolated from groups of fed L. casei Zhang. The sum total of E. coil of fed L. casei Zhang compared with the sum total of E. coil of control groups were low significant（ P 〈 0.01）very much. The results indicated that L. casei Zhang can adhere and grow in the gut of mice and play a part in protection to mice.