1 State Key Laboratory for Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong Special Administrative Region, People's Republic of China; Department of Microbiology, Queen Mary Hospital, Hong Kong Special Administrative Region, People's Republic of China.
2 State Key Laboratory for Emerging Infectious Diseases, Carol Yu Centre for Infection, Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong Special Administrative Region, People's Republic of China; Department of Microbiology, Queen Mary Hospital, Hong Kong Special Administrative Region, People's Republic of China. Electronic address: kelvinto@hku.hk.