Live biotherapeutic products are rapidly changing the landscape of infection prevention, particularly in immunocompromised patients. Among these, SER-155, a multi-strain oral therapy, has demonstrated compelling clinical results. In a recent trial, the incidence of bloodstream infections (BSIs) dropped sharply in the SER-155 group compared to placebo (10% vs. 42.9%). This finding signals a potential breakthrough in both infection control and microbiome modulation. In this interview, Dr. Doris Ponce discusses the mechanisms behind SER-155, its implications for antimicrobial resistance, and its future applications beyond transplant medicine. Her responses provide an in-depth look at how microbiome science is poised to transform not only prevention but also personalized therapeutic strategies in clinical care.