1. Division of Infectious Diseases, Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, Michigan
2. Adult Cystic Fibrosis Program, Brigham and Women's Hospital and Children's Hospital, Boston, Massachusetts
3. Division of Infectious Diseases, Brigham and Women's Hospital, Boston, Massachusetts
4. Laboratorium voor Microbiologie, Universiteit Gent, Ghent, Belgium