[1] Ewha Womans Univ, Coll Med, Dept Pediat, Seoul, South Korea
[2] Ewha Womans Univ, Coll Med, Dept Microbiol, Seoul, South Korea
[3] Seoul Natl Univ, Coll Med, Dept Pediat, Seoul 151, South Korea
[4] Seoul Natl Univ, Coll Med, Dept Surg, Seoul 151, South Korea
[5] Ewha Womans Univ, Coll Med, Dept Internal Med, Seoul, South Korea