Abstract
Targeted gene manipulation in a complex microbial community is an enabling technology for precise microbiome editing. Here we introduce BACTRINS, an in situ microbiome engineering platform designed for efficient and precise genomic insertion of a desired payload and simultaneous knockout of target genes. This system leverages conjugation-mediated delivery of CRISPR-associated transposases to achieve RNA-guided genomic integration, allowing precise insertion of a therapeutic payload while neutralizing pathogen virulence without causing cell death. When applied against an Enterobacteriaceae Shiga toxin-producing pathogen in the gut, this system delivers a CRISPR-associated transposase by bacterial conjugation for site-specific inactivation of the Shiga toxin gene and integration of a nanobody therapeutic payload to disrupt pathogen attachment. A single dose of this therapy results in high-efficiency Shiga gene inactivation and improved survival in a murine infection model of Shiga-producing pathogen. This work establishes a new type of live bacterial therapeutic capable of reducing gut infections by transforming toxigenic pathogens into commensal protectors.