1. Department of Pathology, Peking University, Beijing, China 100083
2. State University of New York Health Science Center at Brooklyn, Brooklyn, NY 11203
3. Department of Microbiology, Peking University, Beijing, China 100083
4. Beijing Ditan Hospital, Beijing, China 100011
5. Hunter Area Pathology Services and Discipline of Anatomical Pathology, University of Newcastle, Newcastle, Australia 2310