1. Department of Respiratory Medicine, National Heart and Lung Institute,1 and
2. Department of Infectious Diseases and Microbiology,2
3. Imperial College, London SW7 2AZ, Veterinary Laboratory Agency, New Haw, Addlestone, Surrey KT15 3NB,3 and
4. Public Health Laboratory Service, Mycobacterium Reference Unit, King's College School of Medicine and Dentistry, King's College Hospital, East Dulwich Grove, London SE22 8QF,4 United Kingdom