Staphylococcus aureus Blood Stream Infection (Bacteraemia) Surveillance. Ceredigion and Mid Wales Trust Data per Bed Days

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1 Staphylococcus aureus Blood Stream Infection (Bacteraemia) Surveillance Ceredigion and Mid Wales Trust Data per Bed Days Commentary: Staphylococcus aureus is a bacterium that a proportion (up to 30%) of the healthy population carry in their nose or in other moist parts of the body. Commonly Staph. aureus causes infections such as boils and infected skin wounds. It can cause pneumonia, urinary tract infections and blood stream infections (bacteraemia) both in the community and in hospital practice. In general terms there are two types of Staph. aureus methicillin sensitive Staph. aureus (MSSA) and methicillin resistant Staph. aureus (MRSA). This simply tells us whether the organism is sensitive or resistant to the commonly used antibiotic flucloxacillin. MRSA stands for methicillin Resistant Staphylococcus aureus (MRSA). It is a type of Staphylcoccus aureus (Staph. aureus) that has become resistant to various antibiotics including flucloxacillin. The infections it causes are the same as those caused by any other Staphylcoccus aureus bacterium. The media are fond of referring to it as the superbug ; however, MRSA is no more of a super bug than ordinary Staph. aureus (MSSA). The absolute numbers of patients diagnosed with MRSA bacteraemia in the Trust are very low, and this simply reflects the patient groups/mix treated. Not all of these bacteraemias are acquired in hospital; some are the reason for admission to hospital. There are very effective antibiotics available to us in hospitals with which we can treat MRSA.

2 Rates of Staphylococcus aureus Blood Stream Infections per For the Staphylococcus aureus blood stream infection (bacteraemia) surveillance scheme, rates produced for reports have historically used 1000 as the standard comparison denominator. However, the Top Ten Blood Stream Infection (bacteraemia) surveillance uses as the standard comparison denominator. To allow comparisons between the two schemes, the Staph. aureus data published for each Trust has been recalculated to be per However to allow comparison with the English scheme, which is presented per 10,000 please divide these Welsh Trust figures by 10. Blood Culture Sets Taken (BCS) Positive Blood Cultures (PBS)* Ceredigion & Mid Wales Annual Data: 01/10/04 30/09/05 Total S.aureus MRSA Bed days % of BCS that are MRSA % of PBS that are MRSA % of S.aureus that are MRSA BCS/ PBS/ Total S.aureus / MRSA/ *Including duplicates and contaminants Quarter Apr 01 - Jun Jul 01 - Sep Oct 01 - Dec Jan 02 - Mar Apr 02 - Jun Jul 02 - Sep Oct 02 - Dec Jan 03 - Mar Apr 03 - Jun Jul 03 - Sep Oct 03 - Dec Jan 04 - Mar Apr 04-Jun Jul 04 - Sep Oct 04 - Dec Jan 05 - Mar Apr 05 - Jun Jul 05 - Sep Ceredigion & Mid Wales Quarterly Trend Data: 01/04/01 30/09/05 Quarter no MRSA MSSA Total S. aureus Bed days MRSA/ MSSA/ SA/

3 Ceredigion & Mid Wales Trust Statistical Process Control Charts for Rates of S. aureus Blood Stream Infections per Bed Days Data from the Staphylococcus aureus blood stream infection (bacteraemia) surveillance are used to produce statistical process control (SPC) charts. These compare a Trust s rate of infection with calculated upper and lower control limits, which allow natural variation in rates to be distinguished from situations where something unusual is occurring. SPC charts are used to compare rates within a Trust over time and between equivalent Trusts at a given point in time. Trusts are asked to investigate if their rates fall outside the control limits of the SPC charts. More information about the statistical analyses performed on the Staph. aureus data and what the results mean is provided in the section on the Staph. aureus Blood Stream Infections surveillance scheme.

4 SPC Chart for Quarterly S. aureus Blood Stream (Bacteraemia) Rates in Ceredigion & Mid Wales Trust: 01/04/01 30/09/05

5 SPC Chart for Quarterly MSSA Blood Stream (Bacteraemia) Rates in Ceredigion & Mid Wales Trust: 01/04/01 30/09/05

6 SPC Chart for Quarterly MRSA Blood Stream (Bacteraemia) Rates in Ceredigion & Mid Wales Trust: 01/04/01 30/09/05