多重耐药菌感染形势严峻，临床亟待结构全新、不易产生耐药、针对性更强的新型抗菌分子，人体共生菌/定植菌是有待挖掘的新型抗菌分子宝库。申请人前期发现健康人鼻腔定植表皮葡萄球菌分泌序列全新的非核糖体肽(NRPs)类抗菌分子，对临床常见的革兰阳性耐药菌具有广谱抗菌活性，且编码该抗菌分子的基因位于可移动质粒上，提示有水平基因转移潜力。申请人接下去将运用菌群培养、转座子插入突变文库筛选、RNA-seq和蛋白组学等技术，结合体外和体内实验，明确健康人鼻腔定植表皮葡萄球菌合成的序列全新的NRPs类抗菌分子被高效转运到细菌外的机制、阐明其杀死/抑制革兰阳性耐药菌的分子机制和作用靶点、分析其抗菌活性的稳定性、对真核细胞的细胞毒性及与其他药物协同/拮抗作用等生物学特征。为后续以该新型天然抗菌分子为基础的药物开发、结构修饰和改造打下理论基础，为以人体共生菌/定植菌作为新型抗菌药物研发资源提供可以借鉴的途径和思路。

The severe drug resistance situation makes the development of new antibacterial drugs as a major scientific problem of global concern. The human flora is a new type of antimicrobial resource need to be studied.Our previous study found that Staphylococcus epidermidis which colonized in healthy human nasal cavity could secreted a new NRPs antibacterial compound composed by NRPSs/ PKSs heterozygous, this new NRPs antibacterial compound had broad spectrum antibacterial activity to clinical Gram-positive bacteria. The gene encoding this new NRPs antibacterial compound is located on a removable plasmid. But it is not clear how this new antibacterial compound be secreted out of the cell and how it kill / inhibit the growth of bacteria. We will next use bacterial culture, transposon insertion mutant library screening, RNA-seq and proteomics, in combination with in vitro and in vivo experiments, elucidating the mechanism of this new antibacterial compound is secreted out of the cell, and killing / inhibiting Gram-positive resistant bacteria. We will analyze the stability of its antibacterial activity, cytotoxicity of eukaryotic cells and other biological characteristics such as synergy / antagonism with other drugs. It provides a reference for the development of a new type of antibacterial drug from human flora/ colonization bacteria.