[1] Massachusetts Gen Hosp, Gastrointestinal Unit, Med Serv, Boston, MA 02114 USA
[2] Harvard Univ, Sch Med, Dept Med, Boston, MA USA
[3] Med Acad Warsaw, Warsaw, Poland
[4] Ankara Univ, Sch Med, TR-06100 Ankara, Turkey
[5] Univ Washington, Seattle, WA 98195 USA
[6] CHU Montreal, Hosp St Luc, Montreal, PQ, Canada
[7] Infekeni Klin, Hradec Kralove, Czech Republic
[8] GlaxoSmithKline, Res Triangle Pk, NC USA
[9] Univ Miami, Miami, FL 33152 USA