An open-label pilot trial reported that a single fecal microbiota transplantation (FMT) dose cleared adherent-invasive E. coli from the gut lining in all evaluable Crohn’s disease patients who carried the organism. The result, focused on targeted colonization of a disease-associated bacterium, provides a mechanistic angle for microbiome therapies beyond symptom-based outcomes. The study’s design emphasizes precision microbiology—identifying a specific bacterial subset and evaluating whether FMT can eliminate it at the mucosal interface. While the cohort size is small, the “all cleared” observation strengthens the case for personalized microbiome targeting. For Crohn’s programs, it also frames a path toward biomarker-guided patient selection and microbiome endpoints that can be measured with higher specificity. Broader translation will hinge on durability of clearance, safety and standardization of FMT, and whether mucosal clearance correlates with clinical remission endpoints in larger trials.