Controllable Engineered Probiotic Hydrogel Coatings Prevent Drainage Tube‐Associated Infections by Disrupting Pathogen Oxidative Stress Responses

Drainage tubes (DTs) are essential medical devices in clinical practice; however, preventing DT-related infections remains a significant challenge. Probiotics are considered a promising alternative therapy, but their cellular activity is susceptible to external stress. Here, we developed a strategy that integrates genetic engineering with a bilayer-structured encapsulation system to create a living probiotic coating for DTs. To enhance the safety and controllability of Saccharomyces boulardii, dual nutrient-deficient strains were constructed. ARO10 was overexpressed to improve the antagonistic activity of S. boulardii by promoting the release of 2-phenylethanol. Scanning electron microscopy and fluorescence imaging demonstrated that sodium alginate microspheres containing engineered probiotics were successfully embedded within a GelMA hydrogel matrix. Results from MTT, ATP, and colony-forming unit assays showed that the double-layer physical barrier not only preserved the cellular activity of the probiotics but also effectively prevented their escape. In co-culture experiments, the coating exhibited inhibitory effects against both Staphylococcus aureus and the hyphal development of Candida albicans. Moreover, RNA sequencing, reverse transcription polymerase chain reaction, and immunohistochemical analyses confirmed that the coating reduced the infective capacity of S. aureus and C. albicans by impairing their oxidative stress responses. Overall, this living probiotic coating offers a promising approach for preventing DT-related infections.