1. Division of Microbiology, School of Biochemistry and Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
2. University Medicine, University of Southampton, Southampton General Hospital, Southampton SO16 6YD, UK
3. Department of Respiratory Medicine, National Heart and Lung Institute, Faculty of Medicine, Imperial College London, Norfolk Place, London W2 1PG, UK
4. GlaxoSmithKline Medicines Research Centre, Stevenage SG1 2NY, UK