[1] Sahlgrens Univ Hosp, Gastroenterol Unit, Dept Internal Med, Gothenburg, Sweden
[2] Univ Gothenburg, Dept Microbiol & Immunol, Inst Biomed, Gothenburg, Sweden
[3] Boras Lasarett, Dept Internal Med, Boras, Sweden
[4] Univ Gothenburg, Dept Clin Bacteriol, Inst Biomed, Gothenburg, Sweden