1. Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain;
2. Microbiology Unit, Hospital Universitario Central de Asturias, Oviedo, Spain;
3. Internal Medicine, Hospital de Cruz Roja, Gijón, Spain;
4. Internal Medicine, Hospital Universitario Central de Asturias, Oviedo, Spain;
5. Internal Medicine, Hospital de Jarrio, Coaña, Spain;
6. Department of Internal Medicine, Fundación Hospital de Aviles, Aviles, Spain;
7. Infectious Diseases Unit, Hospital Universitario de Cabueñes, Gijón, Spain