[1] Emory Univ, Sch Med, Dept Med, Atlanta, GA USA
[2] Duke Univ, Div Infect Dis, Durham, NC USA
[3] Duke Univ, Dept Biostat & Bioinformat, Durham, NC USA
[4] Duke Univ, Duke Clin Res Inst, Durham, NC USA
[5] Duke Univ, Div Gastroenterol, Durham, NC USA