[1] Washington Univ, Sch Med, Div Infect Dis, St Louis, MO 63110 USA
[2] Washington Univ, Sch Med, Dept Pathol & Immunol, St Louis, MO 63110 USA
[3] Washington Univ, Sch Med, Dept Pediat, St Louis, MO 63110 USA
[4] Washington Univ, Sch Med, Dept Surg & Anesthesiol, St Louis, MO 63110 USA