MRSA bacteraemia case counts and rates of community-onset, by sub ICB location (SICBL) and year

Laboratory confirmed cases of MRSA bacteraemia. Community-onset cases are all those that are not hospital-onset cases. Hospital-onset is determined by patient location, date of admission, date of specimen, and patient category. Hospital onset is only indicative for cases where NHS patient specimens are taken on the third day of admission onwards (e.g., day three when day one equals the day of admission) at an acute trust (including cases with unspecified specimen location) for inpatients, day patients, emergency assessment, or unspecified patient category. Records with a missing admission date (where the specimen location is acute trust or missing and the patient category is inpatient, day patient, emergency assessment, or unspecified) are also included. Other cases may have hospital onset, but not in acute trusts. Data is available by Sub ICB ([Integrated Care Board]) location. ## Rationale A long-running voluntary surveillance scheme of laboratory-reported cases of Staphylococcus aureus bacteraemia showed increasing incidence of meticillin-resistant S. aureus (MRSA) infections in England, Wales, and Northern Ireland in the 1990s. This generated both media and public interest. In response, the Department of Health (DH) in England introduced a mandatory surveillance scheme for S. aureus bacteraemias in April 2001, which included data on the number of cases that were due to MRSA. In October 2005, the mandatory surveillance scheme for MRSA bacteraemias was enhanced to collect patient-level data. Additionally, all NHS organisations reporting cases of MRSA bacteraemia from 1 April 2013 were required to complete a Post Infection Review (PIR). This process was commenced to support the delivery of zero tolerance on MRSA bacteraemia, as set out by NHS England in the Planning Guidance [Everyone counts: Planning for Patients 2013/14]. A PIR is undertaken after all MRSA bacteraemias with the purpose of identifying how a case occurred, to identify actions by local healthcare teams which will prevent a reoccurrence, and to identify the organisation best placed to ensure improvements are made (this is known as “assigning” a case to an organisation). From 1 April 2018, the PIR process changed from being applied by all trusts to trusts identified as having high rates of MRSA. For more information, please see [MRSA Guidance: Post Infection Review]. A low value is indicative of a low rate of MRSA. ## Source of numerator UK Health Security Agency (UKHSA), Healthcare Associated Infection Data Capture System (HCAI DCS) Mandatory Surveillance ## Source of denominator Office for National Statistics (ONS), Mid-year population estimates ## Caveats These data do not provide a basis for decisions on the clinical effectiveness of infection control interventions in individual Trusts: further investigations considering potential confounders would need to be undertaken before this could be done. Nor do these data provide a basis for comparisons between acute Trust or SICBLs. Rate information, using rate calculations as currently defined, is not appropriate for comparison. The counts of infections have not been adjusted to give a standardised rate considering factors such as organisational demographics or case mix. Rate information is of use for comparison of an individual organisation over time. ‘All reported cases’ refers to all MRSA-positive blood cultures reported by the Trust whose laboratory processes the specimen. It is important to note that this does not necessarily imply that the infection was acquired there. Confidence intervals for rates are not currently calculated because appropriate methods for comprehensive coverage are being assessed. Cases that the UKHSA’s HCAI Data Capture System attributes to a commissioning hub (such as the national commissioning hub, 13Q, or one of the regional Health & Justice commissioning hubs) are not featured in sub ICB Location dashboards but they do still contribute to the highest spatial level—the England national total. This means the England case total & rates may be slightly higher than the sum of all sub ICB Location cases & rates. IMPORTANT NOTE: SICBL calculations for the period between January 2021 and January 2022 have been based on SICBL boundaries. As such some SICBLs may experience higher or lower rates than expected due to this change. Those SICBLs affected are; Bassetlaw, Glossop, East Leicestershire and Rutland, Lincolnshire, Cambridgeshire and Peterborough, Birmingham and Solihull, Black Country and West Birmingham and Oundle.