1. Department of Medical Microbiology, University of Cape Town and Groote Schuur Hospital, Medical School, Observatory, 7925 Cape Town, South Africa
2. Faculté de Médecine Necker-Enfants malades, Laboratoire de Microbiologie, 156, rue de Vaugirard, 75730 Paris Cedex 15, France
3. Department of Microbiology, University of Cape Town, Rondebosch, 7800 Cape Town, South Africa