[1] Natl Taiwan Univ Hosp, Dept Internal Med, Taipei 100, Taiwan
[2] Natl Taiwan Univ Hosp, Ctr Infect Control, Taipei 100, Taiwan
[3] Kaohsiung Med Univ Hosp, Dept Internal Med, Kaohsiung, Taiwan
[4] Chung Shan Med Univ Hosp, Dept Internal Med, Taichung, Taiwan
[5] Natl Taiwan Univ, Coll Med, Grad Inst Clin Med, Taipei 10764, Taiwan
[6] Natl Taiwan Univ, Coll Med, Sch Nursing, Taipei 10764, Taiwan
[7] Taiwan Ctr Dis Control, Taipei, Taiwan