1. 1Public Health Laboratory, National Public Health Service for Wales, Llandough Hospital, Penlan Road, Penarth CF64 2XX, UK
2. 2Communicable Disease Surveillance Centre, National Public Health Service for Wales, Abton House, Wedal Road, Cardiff CF14 3QX, UK
3. 3Northern Ireland Public Health Laboratory, Bacteriology Department, Belfast City Hospital, Lisburn Road, Belfast BT9 7AD, UK