State Key Laboratory of Food Science and Technology, No. 235 Nanjing East Road, Nanchang, Jiangxi, 330047, PR China; School of Food Science and Technology, Nanchang University, No. 235 Nanjing East Road, Nanchang, Jiangxi, 330047, PR China.
State Key Laboratory of Food Science and Technology, No. 235 Nanjing East Road, Nanchang, Jiangxi, 330047, PR China; School of Food Science and Technology, Nanchang University, No. 235 Nanjing East Road, Nanchang, Jiangxi, 330047, PR China.
Microb Pathog. 2023 Aug;181:106216. doi: 10.1016/j.micpath.2023.106216. Epub 2023 Jun 28.
The subject of this study was to screen lactic acid bacteria (LAB) with pathogen translocation inhibition and investigate the potential inhibition mechanism of it. Pathogens colonized in the intestine could cross the intestinal barrier to access blood circulation, causing severe complications. This study aimed to screen LAB with favorable inhibitory effects on the translocation of enterinvasive Escherichia coli CMCC44305 (E. coli) and Cronobacter sakazakii CMCC45401 (C. sakazakii), which were two common intestinal opportunistic pathogens. After an elaborate screening procedure including adhesion, antibacterial, and translocation assay, Limosilactobacillus fermentum NCU003089 (L. fermentum NCU3089) and Lactiplantibacillus plantarum NCU0011261 (L. plantarum NCU1261) were found to inhibit 58.38% and 66.85% of pathogen translocation, respectively. Subsequently, LAB pre-treatment suppressed the decline in TEER of Caco-2 monolayers caused by pathogens. Meanwhile, L. fermentum NCU3089 significantly inhibited claudin-1, ZO-1, and JAM-1 degradation caused by E. coli, and L. plantarum NCU1261 markedly reduced claudin-1 degradation caused by C. sakazakii. Also, the two LAB strains significantly decreased TNF-α level. In addition, L. fermentum NCU3089 but not L. plantarum NCU1261 tolerated well in the gastrointestinal fluids, and they were both sensitive or intermediate to nine common clinical antibiotics without hemolytic activity. In short, the two LAB strains could inhibit pathogen translocation by competing for adhesion sites, secreting antibacterial substances, reducing inflammatory cytokines levels, and maintaining intestinal barrier integrity. This study provided a feasible solution to prevent pathogen infection and translocation, and the two LAB strains were safe and had potential in food and pharmaceutical applications.
本研究旨在筛选具有抑制病原菌易位作用的乳酸菌（LAB），并探讨其潜在的抑制机制。肠道定植的病原菌可穿过肠屏障进入血液循环，引起严重的并发症。本研究旨在筛选对肠侵袭性大肠杆菌 CMCC44305（E. coli）和阪崎克罗诺杆菌 CMCC45401（C. sakazakii）易位具有良好抑制作用的 LAB，这两种菌都是常见的肠道机会致病菌。经过包括粘附、抑菌和易位测定在内的精心筛选程序，发现发酵乳杆菌 NCU003089（L. fermentum NCU3089）和植物乳杆菌 NCU0011261（L. plantarum NCU1261）可分别抑制 58.38%和 66.85%的病原菌易位。随后，LAB 预处理可抑制病原菌引起的 Caco-2 单层细胞跨上皮电阻（TEER）的下降。同时，L. fermentum NCU3089 显著抑制 E. coli 引起的 Claudin-1、ZO-1 和 JAM-1 的降解，而 L. plantarum NCU1261 则显著降低 C. sakazakii 引起的 Claudin-1 的降解。此外，两种 LAB 菌株均可显著降低 TNF-α水平。此外，L. fermentum NCU3089 可耐受胃肠道液，但 L. plantarum NCU1261 不能耐受胃肠道液，且二者对 9 种常用临床抗生素均敏感或中介，无溶血活性。总之，两种 LAB 菌株可通过竞争黏附位点、分泌抑菌物质、降低炎症细胞因子水平和维持肠道屏障完整性来抑制病原菌易位。本研究为预防病原菌感染和易位提供了可行的解决方案，两种 LAB 菌株均安全且在食品和医药应用中具有潜力。
