Clinical isolates of Fusobacterium nucleatum display strain-specific virulence and modulation by indole derivatives

Pathogenic bacteria adapt to distinct disease environments, but whether these adaptations create therapeutic vulnerabilities remains unclear. Fusobacterium nucleatum has emerged as a key microbial player in colorectal cancer (CRC), yet its strain-specific virulence mechanisms remain poorly defined. In this pilot study of 16 clinical F. nucleatum isolates from CRC patients (n=6), Crohns disease patients (n=6), colon of healthy individuals (n=3), and an oral lesion (n=1), a subset of CRC-derived strains produced 3-4-fold higher levels of endogenous indole. Exogenous indole treatment differentially affected growth and biofilm formation, with some strains increasing biofilm despite growth inhibi