[1] Univ Maryland, Sch Med, Dept Surg, Div Gen & Oncol Surg, Baltimore, MD 21201 USA
[2] Univ Maryland, Sch Med, Dept Med, Div Gastroenterol & Hepatol, Baltimore, MD USA
[3] Univ Maryland, Sch Med, Dept Med, Div Infect Dis, Baltimore, MD USA
[4] Johns Hopkins Univ, Dept Surg, Div Colon & Rectal Surg, Sch Med, Baltimore, MD 21218 USA