1. Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne Medical Center, Cologne, Germany
2. Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, Michigan
3. Pulmonary Medicine/Cystic Fibrosis Center/Allergy, Children's Hospital of Denver, Denver, Colorado
4. Cystic Fibrosis Center Cologne, University Children's Hospital Cologne, University of Cologne Medical Center, Cologne, Germany
5. Laboratory of Microbiology, Ghent University, K. L. Ledeganckstraat 35, B-9000 Ghent, Belgium