[1] Gloucestershire Royal Hosp, Dept Microbiol, Hlth Protect Agcy, Primary Care Unit, Gloucester GL1 3NN, England
[2] Gloucestershire Royal Hosp, Gloucestershire Res & Dev Support Unit, Gloucester GL1 3NN, England
[3] Hlth Protect Agcy Yorkshire & Humber, Leeds, W Yorkshire, England
[4] Cheltenham & Tewkesbury Primary Care Trust, Hlth Protect Agcy Gloucestershire, Hlth Protect Team, Cheltenham, Glos, England
[5] Gloucestershire Royal Hosp, Gloucestershire Hosp NHS Trust, Gloucester GL1 3NN, England
[6] Birmingham Heartlands Hosp, Hlth Protect Agcy W Midlands, Birmingham B9 5ST, W Midlands, England