Unique pathology of colonic spirochaetosis characterised by mucosal eosinophilia is linked to diarrhoea and IBS

Dear Sir, We read with interest the commentary of Raes1 on the growing clinical role of microbiome-based companion diagnostics. We agree that the future of microbiome in medical practice will be in using markers for diagnosis as well as predicting and personalising treatment. We report here new observations on a colonic bacteria that, while traditionally considered a commensal, may be important in chronic diarrhoea and IBS. Colonisation of the colon by Brachyspira aalborgi and B. pilosicoli is characterised by the histological finding of extensive, densely packed, end-on attachment of spirochaetes to the mucosal wall, which is visible on HE bacterial colonisation is dramatically demonstrated by Warthin-Starry staining like Helicobacter pylori (figure 1).2 ,3 The significance of this finding and its role in human disease has been debated in the literature and generally colonic spirochaetosis (CS) is considered to be a …