College of Food Science and Technology, Nanjing Agricultural University, Nanjing, People's Republic of China.
College of Food Science and Technology, Henan Agricultural University, Zhengzhou, People's Republic of China.
Lett Appl Microbiol. 2021 Jul;73(1):54-63. doi: 10.1111/lam.13475. Epub 2021 Apr 15.
Lactic Acid Bacteria (LAB) regulate and maintain the stability of healthy microbial flora, inhibit the adhesion of pathogenic bacteria and promote the colonization of beneficial micro-organisms. The drug resistance and pathogenicity of Salmonella enteritis SE47 isolated from retail eggs were investigated. Meanwhile, Enterococcus faecalis L76 and Lactobacillus salivarius LAB35 were isolated from intestine of chicken. With SE47 as indicator bacteria, the diameters of L76 and LAB35 inhibition zones were 12 mm and 8·5 mm, respectively, by agar inhibition circle method, which indicated that both of them had inhibitory effect on Salmonella, and L76 had better antibacterial effect; two chicken-derived lactic acid bacteria isolates and Salmonella SE47 were incubated with Caco-2. The adhesion index of L76 was 17·5%, which was much higher than that of LAB35 (10·21%) and SE47 (4·89%), this experiment shows that the higher the bacteriostatic effect of potential probiotics, the stronger the adhesion ability; then Caco-2 cells were incubated with different bacteria, and the survival of Caco-2 cells was observed by flow cytometry. Compared with Salmonella SE47, the results showed that lactic acid bacteria isolates could effectively protect Caco-2 cells; finally, after different bacteria incubated Caco-2 cells, according to the cytokine detection kit, the RNA of Caco-2 cells was extracted and transcribed into cDNA, then detected by fluorescence quantitative PCR, the results showed that L76 could protect Caco-2 cells from the invasion of Salmonella SE47, with less cell membrane rupture and lower expression of MIF and TNF genes. Therefore, the lactic acid bacteria isolates can effectively inhibit the adhesion of Salmonella and protect the integrity of intestinal barrier.
乳酸菌（LAB）可以调节和维持健康微生物菌群的稳定性，抑制致病菌的黏附，并促进有益微生物的定植。本研究对从零售鸡蛋中分离的肠炎沙门氏菌 SE47 的耐药性和致病性进行了研究。同时，从鸡肠道中分离出屎肠球菌 L76 和唾液乳杆菌 LAB35。采用琼脂抑制圈法，以 SE47 为指示菌，L76 和 LAB35 的抑菌圈直径分别为 12mm 和 8.5mm，表明两者均对沙门氏菌有抑制作用，且 L76 抑菌效果较好；将两株鸡源乳酸菌分离株与肠炎沙门氏菌 SE47 与 Caco-2 共孵育。L76 的黏附指数为 17.5%，明显高于 LAB35（10.21%）和 SE47（4.89%），表明潜在益生菌的抑菌效果越强，其黏附能力越强；然后用不同的细菌孵育 Caco-2 细胞，通过流式细胞术观察 Caco-2 细胞的存活情况。与肠炎沙门氏菌 SE47 相比，结果表明乳酸菌分离株能有效保护 Caco-2 细胞；最后，用不同的细菌孵育 Caco-2 细胞后，根据细胞因子检测试剂盒提取 Caco-2 细胞的 RNA，反转录成 cDNA，然后进行荧光定量 PCR 检测，结果表明 L76 能保护 Caco-2 细胞免受肠炎沙门氏菌 SE47 的侵袭，细胞破裂较少，MIF 和 TNF 基因表达较低。因此，乳酸菌分离株能有效抑制沙门氏菌的黏附，保护肠道屏障的完整性。
