Staphylococcus aureus (S. aureus) is a bacterium that commonly colonises human skin and mucosa without causing any problems. It can also cause disease, particularly if there is an opportunity for the bacteria to enter the body, for example through broken skin or a medical procedure.
If the bacteria enter the body, illnesses which range from mild to life-threatening may then develop. These include skin and wound infections, infected eczema, abscesses or joint infections, infections of the heart valves (endocarditis), pneumonia and bacteraemia (blood stream infection).
Most strains of S. aureus are sensitive to the more commonly used antibiotics, and infections can be effectively treated. Some S. aureus bacteria are more resistant. Those resistant to the antibiotic meticillin are termed meticillin resistant Staphylococcus aureus (MRSA) and often require different types of antibiotic to treat them. Those that are sensitive to meticillin are termed meticillin susceptible Staphylococcus aureus (MSSA). MRSA and MSSA only differ in their degree of antibiotic resistance: other than that there is no real difference between them.
UK Health Security Agency (UKHSA, formerly Public Health England) has carried out mandatory enhanced surveillance of MRSA bacteraemia since October 2005 and of MSSA bacteraemia since January 2011 for NHS acute trusts; patient-level data of any MRSA and MSSA bacteraemias are reported monthly to UKHSA. Independent sector (IS) healthcare organisations providing regulated activities also undertake surveillance of MRSA and MSSA bacteraemia.
Between 1 April 2013 and 31 March 2018, all positive cases of MRSA bacteraemia were subject to a Post Infection Review (PIR), carried out by the reporting NHS Acute trust and attributable Clinical Commissioning Group. From 1 April 2018 this process is no longer mandatory for all cases and is instead replaced by formal local reviews of MRSA cases for those Trusts and CCGs with the highest MRSA rates. Updated NHS Improvement guidance on MRSA Post Infection Review.
We produce Healthcare associated infections (HCAI) mandatory surveillance statistics publications in accordance with the code of practice for official statistics and they are designated as National Statistics. The data-specific documents below describe our compliance with aspects of the Code.