Salmonella is a common food-borne pathogen; since lactobacilli show great potential for protecting against Salmonella infections, they are used as dietary supplements in functional foods. The aim of this study is to investigate the strain-specific properties and the involved mechanisms of action of Lactobacillus plantarum towards prevention of Salmonella infection. Mice were pretreated with mixed strains or single strain of Lactobacillus plantarum for 10 d prior to infection with Salmonella typhimurium SL1344, and the survival rates showed that lactobacilli exhibited strain-specific properties for preventing Salmonella infection. Then, in vitro and in vivo studies were carried out to investigate the involved mechanism of the strain-specific properties. The results showed that different Lactobacillus plantarum strains had different effects on inhibiting Salmonella growth, thus preventing adhesion to and invasion of epithelial cells by pathogens and enhancing immune responses. The present study demonstrated strain-specific properties of probiotics to prevent Salmonella infection and elucidated their underlying mechanisms.

Pathogen-induced infectious diseases pose great threats to public health. Accordingly, many studies have investigated effective strategies targeting pathogenic infections. We previously reported the preventive effects of Lactobacillus plantarum ZS2058 (ZS2058) and L. rhamnosus GG (LGG) against Salmonella spp. in a murine model. Here, we compared the mechanisms underlying the preventive effects of these Lactobacillus strains in vivo . Notably, reduced C-reactive protein levels were observed with both ZS2058 and LGG, which suggests abrogated anti-infection and inflammatory responses. ZS2058 more efficiently reduced the pathogenicity of Salmonella by increasing the level of propionic acid in feces and production of mucin 2 in the mouse colon and activity through the interleukin (IL)-23/IL-22 and IL-23/IL-17 pathways. Meanwhile, LGG more strongly alleviated gut inflammation, as indicated by changes in the levels of tissue necrosis factor (TNF)-α, IL-10 and myeloperoxidase (MPO) in infected mice. Moreover, both ZS2058 and LGG restored the levels of interferon (INF)-γ, a cytokine suppressed by Salmonella , albeit through different pathways. Our results demonstrate that ZS2058 and LGG prevent Salmonella infection via different mechanisms.

Chronic nonbacterial prostatitis (CNP) is a common male disease with high incidence and low cure rate. This study aims to investigate the anti-CNP potential of Poria cocos polysaccharides (PPs) in a λ-carrageenan-induced CNP rat model. Results showed that PPs exerted anti-CNP functions by reducing the prostate weight and prostate index as well as the level of C-reactive protein (CRP) and pro-inflammatory cytokines (TNF-α and IL-1β). Further analysis on sex hormones revealed that PPs could favor CNP alleviation by regulating the production of testosterone (T), dihydrotestosterone (DTH), and estradiol (E2). PPs could also alleviate CNP by regulating the level of inducible nitric oxide synthase (iNOS), malonaldehyde (MDA), and superoxide diamutase (SOD) in inflamed prostate, thereby enhancing the anti-oxidative stress activity. As most non-digestive polysaccharides are fermented by gut microbiota rather than being digested directly by the host, we further analyzed PP-induced changes in gut microbiota. Microbiomic analysis revealed that PPs significantly change the profile of gut microbiota. Moreover, the relative abundance of five genera was recovered by PPs with a dose−effect relationship, thereby being suggested to play critical roles in the alleviation of CNP. Epigenomic (methylomic) analysis showed that PPs remodeled the DNA methylome of intestinal epithelia, by which PPs might modify hormone production. In the present study, we reported the anti-CNP activity of PPs as well as the involved mechanisms.