1. School of Applied Sciences, RMIT University, Plenty Road, Bundoora, P.O. Box 71, Victoria 3083, Australia
2. Department of Microbiology, Royal Children's Hospital, Flemington Rd., Parkville, Victoria 3052, Australia
3. Department of Microbiology and Infectious Diseases, Royal Women's Hospital, Victoria, 132 Grattan St., Carlton, Victoria 3053, Australia
4. Department of Obstetrics and Gynaecology, University of Melbourne, Victoria 3010, Australia