1. Institute for Experimental Treatment of Cystic Fibrosis, Scientific Institute H. S. Raffaele, Milano, Italy
2. Servicio de Microbiologìa Hospital Son Dureta, Palma de Mallorca, Spain
3. Dipartimento di Scienze Biomolecolari e Biotecnologie, Università degli Studi di Milano, Milano, Italy
4. Klinische Forschergruppe, OE 6710, Medizinische Hochschule Hannover, Hannover, Germany
5. Ospedale Maggiore Policlinico, CF Clinic, Milano, Italy
6. Institute of Medical Microbiology and Hygiene, Universitätsklinikum Tübingen, Tübingen, Germany