Methods capable of manipulating bacterial colonization are of great significance for modulating host-microbiota relationships. Here, we describe a strategy of in-situ chemical reaction-mediated covalent localization of bacteria. Through a simple one-step imidoester reaction, primary amino groups on bacterial surface can be converted to free thiols under cytocompatible conditions. Surface thiolation is applicable to modify diverse strains and the number of introduced thiols per bacterium can be easily tuned by varying feed ratios. These chemically reactive bacteria are able to spontaneously bond with mucous layer by catalyst-free thiol-disulfide exchange between mucin-associated disulfides and newly converted thiols on bacterial surface and show thiolation level-dependent attachment. Bacteria optimized with 9.3 × 10⁷ thiols per cell achieve 170-fold higher attachment in mucin-enriched jejunum, a challenging location for gut microbiota to colonize. As a proof-of-concept application for microbiota transplantation, covalent bonding-assisted localization of an oral probiotic in the jejunum generates an improved remission of jejunal mucositis. Our findings demonstrate that transforming bacteria with a reactive surface provides an approach to chemically control bacterial localization, which is highly desirable for developing next-generation bacterial living bioagents.

能够操纵细菌定植的方法对于调节宿主-微生物群的关系具有重要意义。在这里，我们描述了原位化学反应介导的细菌共价定位策略。通过简单的一步亚胺酯反应，细菌表面的伯氨基可以在细胞相容性条件下转化为游离硫醇。表面硫醇化适用于修饰不同的菌株，每个细菌引入的硫醇数量可以通过不同的进料比轻松调整。这些化学反应性细菌能够通过粘蛋白相关二硫化物和细菌表面新转化的硫醇之间的无催化剂硫醇-二硫化物交换自发地与粘膜层结合，并显示硫醇化水平依赖性附着。用 9.3 × 10 ^{7优化的细菌}每个细胞的硫醇在富含粘蛋白的空肠中达到 170 倍的高附着，这是肠道微生物群定植的一个具有挑战性的位置。作为微生物群移植的概念验证应用，口服益生菌在空肠中的共价键辅助定位可改善空肠粘膜炎的缓解。我们的研究结果表明，转化具有反应性表面的细菌提供了一种化学控制细菌定位的方法，这对于开发下一代细菌活生物制剂是非常理想的。