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