Comment on “Effectiveness and safety of oral vancomycin for the treatment of inflammatory bowel disease associated with primary sclerosing cholangitis: a systematic review and pooled analysis” - Richard Kellermayer; Peter Lewindon; Cynthia Buness; James Tabibian; Kevin Johnson; Shamita Shah; Parambir Dulai; Ahmad H. Ali; Ayesha Shah; Gerald Holtmann; Harland S. Winter (Therapeutic Advances in Gastroenterology)