On the “subclades” of Fusobacterium animalis and colorectal cancer

There is a well-documented association between Fusobacterium animalis and colorectal cancer in humans. In their recent paper “A distinct Fusobacterium nucleatum clade dominates the colorectal cancer niche”, Zepeda-Rivera and co-authors claim that F. animalis contains two distinct “subclades”, and that only one of these are associated with colorectal cancer whereas the other is associated with the oral cavity. By re-assessment of their data, it is clear that this hypothesis is based on a wrongful interpretation of phylogenetic data. The “subclade” associated with colorectal cancer represents F. animalis as already known, whereas the “subclade” not associated with colorectal cancer represents the recently described species Fusobacterium watanabei.