Healthcare-associated infections

We analyse changes in annual counts of healthcare-associated infections including MRSA, C. difficile and E. coli.


Last updated: 29/01/2020

Effective clinical care Safety
Primary and community care Hospital care


Clostridioides difficile (C. difficile), methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli (E. coli) are bacterial infections that commonly occur as a direct result of healthcare interventions (such as medical or surgical treatment), or from being in contact with a healthcare setting. They are the most well known healthcare-associated infections (HCAIs). HCAIs pose a serious risk to patients, staff and visitors, can incur high costs for the NHS, and can cause significant morbidity to those infected. As a result, infection prevention and control is a key priority for the NHS.

How has the frequency of reported Clostridioides difficile infections changed over time? 29/01/2020

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In 2007, the levels of healthcare-associated infections, including C. difficile, became a major national concern, in particular following the Healthcare Commission’s investigation into Maidstone and Tunbridge Wells NHS Trust (Healthcare Commission, 2007). Action to address these problems was far-reaching and included new legislation as well as focussed investment, regulation and performance monitoring against targets. Following this focus in 2007, the total number of C. difficile infections decreased year-on-year to reach a low of 13,362 cases in 2013/14. 

In 2014/15 there was a slight increase in C. difficile infections from the previous year, a 4% increase for hospital-onset cases and an 8% increase for community-onset cases. Since then, the number of C. difficile infections has fluctuated. In 2018/19, there were 4,201 hospital-onset cases and 8,074 community-onset cases.

How has the frequency of MRSA infections changed over time? 29/01/2020

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In 2007, the level of healthcare-associated MRSA infections also became a major national concern, similar to C. difficile. The reduction in the number of MRSA cases has followed a broadly similar trajectory to that of C. difficile. Between 2007/08 and 2013/14, there was an 81% reduction in total cases (a 90% reduction in hospital-onset cases and a 70% reduction in community-onset cases). Despite this reduction, the number of MRSA cases increased slightly in 2015/16 and has fluctuated since then. In 2018/19, there was a 2% decrease in hospital-onset cases and a 7% decrease in community-onset cases.

How has the frequency of Escherichia coli infections changed over time? 29/01/2020

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Enhanced surveillance of E. coli bacteria has been mandatory for NHS acute trusts since June 2011. Following a worrying increase in E.coli infections, the NHS Patient Safety Strategy includes a goal to decrease healthcare associated Gram-negative bloodstream infections by 25% by 2021 and halve them by 2024. E. coli represents 55% of all Gram-negative bloodstream infections, and reducing the number of E. coli infections is an important safety issue. Preventing bloodstream infections would also reduce the need to prescribe antimicrobials, which is a key way of reducing the rise in antibiotic resistance.

Between 2012/13 and 2018/19, the total number of E. coli infections increased by 34%, from 32,309 to 43,242. The number of community-onset cases increased by 44%, but the number of hospital-onset cases only increased by 1%. The increase is likely to reflect higher rates of blood culture testing as awareness of sepsis risk has increased. 

About this data

The bacterial infections are deemed to be hospital-onset if the following rules are met:

  • the location where the specimen was taken is given as 'acute trust' or is not known;
  • the patient was either an 'In-patient', 'Day-patient', in 'Emergency assessment' or is not known;
  • the patient's specimen date is on, or after, the third day of the admission (for MRSA and E. coli) or the fourth day of the admission (for C. difficile), where the day of admission is day 1.

If the above rules are not met, then cases are deemed to be community-onset.