Abstract
Rapid development of synthetic biology has led to engineered probiotics to address the growing concern of infectious diseases and cancer. Dual or multiple bacterial infections are becoming more frequent, but there are few treatment options because complex approaches are needed to address different disease mechanisms. In this study, we designed a minimal logic gate to program E. coli Nissle 1917 to detect and treat the disease caused by Pseudomonas aeruginosa and Yersinia enterocolitica. Two orthogonal gene circuits were verified to detect and kill the two pathogens, respectively. The "AND" gate was designed and engineered to achieve remarkable chemotaxis and killing effects in vitro when both pathogens existed. Then, we demonstrated the preventive and therapeutic effectiveness of the programmed EcN against P. aeruginosa and Y. enterocolitica in a murine model of intestinal infection. The proof-of-concept of our programmed EcN strategy demonstrates an exciting potential method for preventing and treating dual-bacterial infection.