Screening Of New Delivery Vehicles For Lactobacillus And Research On Oral Vaccine Of Staphylococcus Aureus

Staphylococcus aureus?S.aureus?can cause bacteremia,pneumonia and many other diseases.It is one of the important pathogens that cause body infection.In recent years,antibiotic-resistant strains have caused more and more resistant strains.The control of S.aureus infection is becoming more and more difficult,and the difficulty of preventing and treating for us is increasing.The research and development of Staphylococcus aureus vaccine may be an effective means to prevent its infection.Therefore,the development of a safe and effective Staphylococcus aureus vaccine is imminent.S.aureus can infect the body through the mucosal route.S.aureus mucosal vaccine may be an effective way to prevent Staphylococcus aureus infection.Mucosal immunity requires an antigen presentation system that can effectively avoid degradation and can stimulate the body to produce an immune response;both lactic acid bacteria and attenuated pathogenic bacteria can be used as delivery vehicles to deliver antigens,but the attenuated pathogenic bacteria may have virulence recovery,And Lactobacillus is widely used and safe and non-toxic,so it has become a good delivery vehicle.In this study,lactic acid bacteria were isolated,identified and screened from traditional dairy products.Lactobacillus with better probiotic effects was selected to deliver S.aureus antigens Csa1,TraP,MntC,Hla_H35L,and their immunoprotective effects were evaluated.The specific research results are as follows:1.A total of 155 strains of lactic acid bacteria were isolated from traditional dairy products,of which 73 strains of were roughly divided into 9 types,including:Lactobacillus plantarum,Lactobacillus reuteri,Lactobacillus paracasei,Lactobacillus crustorum,Lactobacillus helveticus,Lactobacillus coryniformis,Lactobacillus diolivorans,Lactobacillus fermentum,Lactobacillus zeae.2.Lactobacillus WXD114,WXD169,WXD171,WXD176,WXD178 have strong tolerance to artificial gastric juice bile saltsand intestinal fluid,adhesion to cells,and strong antibacterial ability in vitro.3.Choose four strains of WXD114,WXD171,WXD176,WXD234as delivery vectors and WXD114(pNZ8148-csa1/traP/mntC/hla_H35L),WXD171(pNZ8148-csa1/traP/mntC/hla_H35L),WXD176(pNZ8148-csa1/traP/mntC/hla_H35L),and WXD234?pNZ8148-csa1/traP/mntC?were successfully constructed,these 15 strains of recombinant Lactobacillus can successfully express exogenous antigens Csa1,TraP,MntC and Hla _H35L,and their physiology compared with wild bacteria,there is no obvious change in characteristics,and it can be stably inherited.4.After immunizing mice with recombinant Lactobacillus separately,they were infected with Staphylococcus aureus.The statistics of the survival rate of the mice showed that the use of Lactobaillusreuteri WXD176 as the carrier to deliver the antigen was the best.Among them,the protective effect of the delivery antigen Hla _H35L is better than MntC,TraP,Csa1.