Hydrogel coatings of catheters have attracted extensive attention in the field of medical devices due to its hydrophilicity and softness, while scarcities of Janus adhesion, adaptive antibacterial property, and real-time disease monitoring restricted their clinical translational applications. Herein, a novel hydrogel coating with water-responsive Janus adhesion and acidity-triggered transformation was fabricated for antibacterial treatment and fluorescence diagnosis of catheters-associated infections. First, a sufficient adhesion strength of 44.6 ± 1.9 kPa effectively prevented shedding of the hydrogel coating during catheterization, and meanwhile a super-lubricated layer with an extremely-low coefficient of friction of about 0.03 was formed to reduce friction pain in an aqueous microenvironment. Furthermore, size and fluorescence intensity of chitosan/bovine serum albumin-gold nanoparticles within the hydrogel were varied with pH due to acidity-triggered transformation, where an adaptive release of antibacterial nanoparticles was achieved to reduce biofilms formation and alleviate inflammation degree synergistically. More importantly, such antibacterial treatment was monitored in real-time dependent on an on–off variation of fluorescence intensity. Overall, amounts of in-vitro and in-vivo results performed in rabbit urinary tract infection model and porcine tracheal intubation model fully suggested our newly-synthesized hydrogel coating on universal medical devices showed a promising potential for integrated diagnosis and treatment of catheters-associated infections.