Provided are compositions and methods based in part on the discovery that Enterococcus faecium heterologous secreted antigen A (SagA)-produced peptidoglycan fragments are protective against enteric bacterial infections. Modified bacteria that are engineered to express heterologous SagA are provided, and are included a nutraceutical, pharmaceutical, and probiotic forulations, and as components of food products, including dairy products. The modified bacteria include modified Lactobacillus bacteria that express heterologous SagA. The disclosure includes a method that involves introducing into an individual modified bacteria of that express and secrete heterologous SagA. The disclosure provides isolated peptidoglycan fragment preparations made by a exposing a composition that contains peptidoglycan to an isolated or recombinant SagA, or to modified bacteria expressing a heterologous SagA, allowing SagA to generate the peptidoglycan fragments, and separating the peptidoglycan fragments from the composition to obtain the isolated peptidoglycan fragments or a preparation that contains them.
本发明涉及一种基于发现Enterococcus faecium异源分泌抗原A(SagA)产生的肽聚糖片段对抗肠道细菌感染的组合物和方法。提供了经过改造的细菌,这些细菌被工程化以表达异源SagA,并包括营养保健品、制药和益生菌制剂以及食品产品的组成部分,包括乳制品。这些改造的细菌包括表达异源SagA的改造
乳酸菌。本公开还包括一种方法,涉及将表达和分泌异源SagA的改造细菌引入个体中。本公开提供了通过将含有肽聚糖的组合物暴露于分离或
重组的SagA或表达异源SagA的改造细菌中来制备孤立的肽聚糖片段制剂的方法,并允许SagA生成肽聚糖片段,并将肽聚糖片段与组合物分离以获得孤立的肽聚糖片段或包含它们的制剂。