1. Communicable Disease Control, Department of Human Services, Melbourne, VIC.
2. National Centre for Epidemiology and Population Health, Australian National University, Canberra, ACT.
3. Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology, University of Melbourne, Melbourne, VIC.
4. St Vincent's Hospital Melbourne, Melbourne, VIC.
5. University of Melbourne, Melbourne, VIC.