Participating Centres
Centres have contributed data for different periods, and new laboratories join the study each year.
The centres which have contributed data, together with the earliest and latest months for which full data are available, are as follows:
| Participating Centre |  | Date started | | Latest month for which data available |
| Ashford: William Harvey Hospital | | January 2002 | | May 2008 |
| Birmingham: West Midlands HPA Laboratory, Heartlands Hospital | | January 2002 | | May 2008 |
| Bristol: Bristol HPA Laboratory | | April 2006 | | May 2008 |
| Cambridge: Cambridge HPA Laboratory, Addenbrooke's Hospital | | January 2002 | | May 2008 |
| Chester: Chester HPA Laboratory (via Manchester) | | January 2002 | | May 2008 |
| Grimsby: Diana Princess of Wales Hospital | | April 2004 | | May 2008 |
| Hull: Castle Hill Hospital | | April 2002 | | April 2007 |
| Leeds: Leeds General Infirmary & St James' Hospital | | September 2004 | | May 2008 |
| Leeds: Leeds HPA Laboratory (No longer active) | | January 2002 | | July 2005 |
| Liverpool: Liverpool HPA Laboratory (via Manchester) | | January 2002 | | May 2008 |
| Liverpool: Royal Liverpool University Hospital | | January 2002 | | May 2008 |
| London: Centre for Infections | | January 2002 | | May 2008 |
| London: Ealing Hospital (No longer active) | | November 2002 | | October 2003 |
| London: North Middlesex Hospital | | July 2002 | | May 2008 |
| London: St Bartholomew's Hospital | | August 2004 | | March 2008 |
| London: St George's Hospital | | January 2002 | | May 2008 |
| London: University College Hospital | | September 2004 | | May 2008 |
| Manchester: Manchester Medical Microbiology Partnership, Manchester Royal Infirmary | | January 2002 | | May 2008 |
| Newcastle: Newcastle HPA Laboratory | | January 2002 | | May 2008 |
| Nottingham: Queen's Medical Centre | | September 2002 | | May 2008 |
| Portsmouth: St Mary's Hospital | | January 2002 | | June 2008 |
| Preston: Preston HPA Laboratory (via Manchester) | | January 2002 | | May 2008 |