1 Division of Infectious Diseases, Cheng-Hsin General Hospital, Taipei, Taiwan, ROC.
2 Division of Microbiology, Department of Pathology and Laboratory Medicine, Taipei, Taiwan, ROC; Division of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC; Institute of Public Health, National Yang-Ming University, Taipei, Taiwan, ROC. Electronic address: yjchan@vghtpe.gov.tw.