1 Division of Infectious disease, Medical University Cluster, National University Hospital, National University Health System, Singapore.
2 Department of Laboratory Medicine, National University Hospital, National University Health System, Singapore.
3 Department of Pathology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
4 Clinical Microbiology, Leicester Royal Infirmary, University Hospitals of Leicester NHS Trust, 5/F Sandringham Building, Infirmary Square, Leicester LE1 5WW, UK; Department of Respiratory Sciences, University of Leicester, Leicester, UK. Electronic address: [email protected].
5 National Centre for Infectious Diseases, Singapore; Department of Infectious Diseases, Tan Tock Seng Hospital, Singapore.