Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, PR China.
Food Funct. 2020 May 1;11(5):4697-4706. doi: 10.1039/d0fo00905a. Epub 2020 May 14.
Lactobacillus spp., as probiotics, have shown efficacy in the inhibition of pathogenic bacteria in the intestinal tract. In this study, we investigated the antibacterial activity of Lactobacillus casei NA-2, which was isolated from northeast sauerkraut in China. The results of co-culture suggested that L. casei NA-2 could inhibit the growth of Bacillus cereus, Staphylococcus aureus, Salmonella typhimurium and Escherichia coli O157:H7. Moreover, L. casei NA-2 could adhere to the four pathogenic bacteria potentially associated with its exopolysaccharide (EPS). EPS from L. casei NA-2 was then isolated and its activity determined. The results showed that EPS inhibited the biofilms of B. cereus, S. aureus, S. typhimurium and E. coli O157:H7, with the highest inhibition ratios of 95.5% ± 0.1%, 30.2% ± 3.3%, 14.3% ± 0.6%, and 16.9% ± 5.4%, respectively. Moreover, EPS was able to disperse B. cereus, S. aureus, S. typhimurium and E. coli O157:H7 by 94.1% ± 1.2%, 31.8% ± 8.6%, 40.8% ± 3.3% and 49.6% ± 3.8%, respectively. Results showed that EPS from L. casei NA-2 have potential antibacterial properties by inhibiting biofilm formation and dispersing pathogenic bacteria. In conclusion, the antibiofilm property of the EPS on the surface of L. casei NA-2 is one of the possible reasons for antibacterial activity of L. casei NA-2.
植物乳杆菌作为益生菌已被证明具有抑制肠道中致病菌的功效。在这项研究中，我们研究了从中国东北酸菜中分离出的干酪乳杆菌 NA-2 的抗菌活性。共培养结果表明，干酪乳杆菌 NA-2 可以抑制蜡样芽孢杆菌、金黄色葡萄球菌、鼠伤寒沙门氏菌和大肠杆菌 O157:H7 的生长。此外，干酪乳杆菌 NA-2 可以潜在地附着在与其胞外多糖（EPS）相关的四种致病性细菌上。然后分离出干酪乳杆菌 NA-2 的 EPS 并测定其活性。结果表明，EPS 抑制了蜡样芽孢杆菌、金黄色葡萄球菌、鼠伤寒沙门氏菌和大肠杆菌 O157:H7 的生物膜形成，抑制率最高分别为 95.5%±0.1%、30.2%±3.3%、14.3%±0.6%和 16.9%±5.4%。此外，EPS 能够分别通过 94.1%±1.2%、31.8%±8.6%、40.8%±3.3%和 49.6%±3.8%分散蜡样芽孢杆菌、金黄色葡萄球菌、鼠伤寒沙门氏菌和大肠杆菌 O157:H7。结果表明，干酪乳杆菌 NA-2 的 EPS 具有抑制生物膜形成和分散致病菌的潜在抗菌特性。总之，干酪乳杆菌 NA-2 表面 EPS 的抗生物膜特性是其抗菌活性的可能原因之一。
