[1] Univ Nottingham, Inst Infect Immun & Inflammat, Nottingham NG7 2UH, England
[2] Nottingham Univ Hosp NHS Trust, Nottingham NG7 2UH, England
[3] Univ Nottingham, Div Gastroenterol, Nottingham NG7 2UH, England
[4] Univ Nottingham, Dept Clin Microbiol, Nottingham NG7 2UH, England