1. Centre for Enteric Diseases, National Institute for Communicable Diseases, Division of the National Health Laboratory Service, Johannesburg, South Africa
2. Department of Medical Microbiology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
3. National Health Laboratory Service, Tygerberg Hospital, Cape Town, South Africa
4. Department of Pathology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
5. Communicable Disease Control, Service Priorities Coordination, Department of Health, Cape Town, South Africa