1. Departamento de Immunologia, Microbiologia y Parasitologia, Facultad de Medicina y Odontologia, Universidad del Pais Vasco, 48080 Bilbao, Spain
2. Molecular Diagnostics & Typing Unit, Public Health Laboratory, University Hospital, Queen's Medical Centre, Nottingham NG7 2UH
3. Antibiotic Resistance Monitoring and Reference Laboratory, Central Public Health Laboratory, London NW9 5HT, United Kingdom