Protective Effect Of Oral Probiotics On Salmonella Infection In Mice

Salmonellosis is the three leading causes of human death and one of the most important foodborne diseases.Animals are the main source of salmonella,and animal-based food is the main route of transmission to humans.Therefore,controlling the infection of this disease at its source can help in the future to effectively control and control salmonella throughout the food chain on a global scale.Early studies have shown that people were initially given antibiotics to prevent and treat salmonella.In the beginning,it does show initial benefit,but the side effects are very big.Salmonella has evolved over time.So far,salmonella has evolved multiple drug-resistant serotypes,as a result of people’s obsession with changing antibiotic types to treat salmonella.Probiotics are one of them.Nissle 1917(ECN),one of the probiotics,has a great advantage in the competition with pathogenic bacteria due to its unique adaptive properties and safety to host.In this study,the widely used probiotic Nissle 1917 was selected.Mices were first given oral Nissle 1917,and then mice in each group were challenged with Salmonella.Pathological changes of liver,spleen and intestinal tract of mice were observed after attack,the number of viable bacteria in liver was detected,and the survival rate of mice was recorded.By observing the paraffin sections of the mouse tissues,it was found that Nissle 1917 could significantly reduce the damage of Salmonella to the mouse tissues.The livable count of Salmonella in mouse liver showed that Nissle 1917 could reduce the invasion of Salmonella in mouse liver.In addition,Nissle 1917 had a protective effect on Salmonella infection in mice based on body weight and survival rate.This experiment confirmed that probiotics can change the intestinal flora of mice infected with Salmonella.Mice were given oral probiotics and challenged.The feces of infected mice were collected and sequenced for 16 S amplicon.The results showed that the structure of intestinal microflora in both groups was changed.The decrease in the abundance of Romboutsia,Bacteriostasis,and Clostridium indicated that Salmonella infection may lead to intestinal mucosal lesions in mice.Among them,the abundance of Lactobacillaceae,Trichelicaceae and Rumen Bacteriaceae increased significantly,indicating that probiotics can promote the proliferation of Lactobacillaceae in the intestine.The above experimental results prove that Nissle 1917 used in this study has a protective effect on mice infected with Salmonella and can be used as a candidate strain of microecologics.