1. Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain
2. Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
3. CIBER de Enfermedades Respiratorias (CIBERES CB06/06/0058), Madrid, Spain
4. Medicine Department, School of Medicine, Universidad Complutense de Madrid (UCM), Madrid, Spain
5. Instituto de Salud Carlos III, Madrid, Spain