利用益生菌调节肠道微生物群防治多种疾病已成为国际研究热点。尽管传统益生菌在营养代谢、抑制病原菌、诱导免疫调节和维护肠道上皮屏障功能方面具有一定的调节作用，但无法治疗某些疾病。近年来，受到合成生物学的不断发展的助推，设计和构建具有所需特性和功能的益生菌以造福人类健康已取得重大进展。在本文中，我们总结了传统益生菌的作用机制及其局限性，并重点介绍了设计和构建益生菌作为生活诊断和治疗工具来检测和治疗一系列疾病，包括病原菌感染、癌症、肠道炎症、代谢性疾病、疫苗递送、认知健康和脂肪肝等。此外，我们讨论了关于工程益生菌的疑虑及相应的对策，并概述了未来发展工程活生物治疗产品所需的特性。

The use of probiotics to regulate the intestinal microbiota to prevent and treat a large number of disorders and diseases has been an international research hotspot. Although conventional probiotics have a certain regulatory role in nutrient metabolism, inhibiting pathogens, inducing immune regulation, and maintaining intestinal epithelial barrier function, they are unable to treat certain diseases. In recent years, aided by the continuous development of synthetic biology, engineering probiotics with desired characteristics and functionalities to benefit human health has made significant progress. In this article, we summarise the mechanism of action of conventional probiotics and their limitations and highlight the latest developments in the design and construction of probiotics as living diagnostics and therapeutics for the detection and treatment of a series of diseases, including pathogen infections, cancer, intestinal inflammation, metabolic disorders, vaccine delivery, cognitive health, and fatty liver. Besides we discuss the concerns regarding engineered probiotics and corresponding countermeasures and outline the desired features in the future development of engineered live biotherapeutics.