Two-component signaling system OrhK/OrhR increases pathogenicity of uropathogenic Escherichia coli CFT073 by upregulating type 1 fimbriae expression to promote IBCs formation

The central scientific question was whether and how OrhK/R promotes infection by affecting bacterial colonization. To address this, we conducted a series of experiments focusing on in vivo colonization, the formation of key bacterial structures (IBCs and type 1 fimbriae), and the sensing of environmental signals (ROS).

Specific work included: assessing bacterial loads in mouse bladders and kidneys through infection models; counting and imaging intracellular bacterial communities (IBCs) in bladder tissues using microscopy; detecting the expression of related genes and the production of fimbriae using molecular biology techniques (e.g., qPCR, RNA-seq, hemagglutination assay); and validating the role of reactive oxygen species (ROS) in this signaling pathway through chemical intervention (using the antioxidant NAC).