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Health Care Associated Infection (HCAI)

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Health Care Associated Infections (HCAI) are infections resulting from medical care or treatments in a hospital setting, primary care setting, nursing home, or the patient's own home - this definition of HCAI reflects the fact that healthcare has changed and is now often performed outside a hospital environment. HCAI's can affect any part of the body but in the UK, the gastrointestinal and respiratory systems and the urinary tract are most commonly affected.

HCAI covers a wide range of infections. The most well known include those caused by Meticillin-resistant Staphylococcus aureus (MRSA), Meticillin-sensitive Staphylococcus aureus (MSSA), Clostridium difficile (C.diff) and Escherichia coli (E coli).

HCAIs potentially pose a risk to patients, clients and staff arising from treatment and care in hospital and primary care settings. They can incur significant costs for the NHS and others, and cause significant morbidity and mortality for those infected.  As a result, Infection Prevention and Control is a key priority for the NHS, and Public Health England (PHE) has a responsibility to advise and support the NHS and others in their efforts to prevent HCAIs and any associated risks to health.

Facts and figures

For Clinical Commissioning Groups (CCG) there is an expectation to continually increase standards of infection control to limit the incidence of HCAI, with the overall aim of eradicating them completely. A zero tolerance approach to MRSA and a significant reduction of reported C.diff are linked to better patient outcomes (or a lack of harmful outcome).

PHEs annual epidemiological commentary on HCAIs reports that across England the rate of MRSA bacteraemia (bloodstream infection, not colonisation on the skin) cases dropped by 7.1% in 2014/15 compared to the previous financial year (1.5 vs. 1.6 per 100,000 population). However, counts and rates of C. difficile infections (antibiotic-associated infection) and both MSSA and E. coli bacteraemias have significantly increased in 2014/15 compared to 2013/14.

The increases in C.diff infection are currently under investigation by PHE, in particular, the proportion of infections detected in the community that may be associated with recent hospital stays and inappropriate prescribing of antibiotics. Increases in MSSA and E. coli bacteraemia numbers have been apparent for some time and PHE are currently working with the Advisory Committee on Antimicrobial Resistance and Healthcare Associated Infection (ARHAI) to identify suitable healthcare interventions to reduce these infections. A common pattern across all four infections was the high percentage of cases which would not traditionally have been defined as hospital-onset. Even among inpatients, the percentage considered as hospital-onset has decreased over time. However, with the increasing proportion of ostensibly community acquired infections both control and surveillance measures will need to support this setting if reductions in infections are to continue1.

    • In 2014/15, Blackpool hospitals, had only 5 reported cases of MRSA (bloodstream infection), a rate of 1.9 per 100,000 bed days. This compares with 2.3 per 100,000 bed days nationally.
    • Although Blackpool CCG2 saw a slight rise in the rate of MRSA infection from 2.1 per 100,000 population in 2013/14 to 2.8 per 100,000 in 2014/15 the increase was not significant.
    • There were 122 cases of C.difficile reported by Blackpool hospitals in 2014/15, a rate of 46.5 per 100,000 bed days compared to 41.0 nationally.

Figure 1 shows the trend in rates of C.difficile infection apportioned between the hospital and the CCG2. Cases in Blackpool have risen slightly in 2014/15 in both the hospital and the CCG after falling over the previous few years. Rates in the CCG have risen from 33.1 per 100,000 population (47 cases) in 2012/13 to 50.9 per 100,000 (72 cases) in 2014/15. Blackpool hospital has seen a similar rise, going from 10.4 per 100,000 bed days (28 cases) to 20.6 per 100,000 (54 cases) over the same period.

Figure 1: Trend in rates of C.difficile - hospital and CCG apportioned cases

Figure 2: Trend in rates of C.difficile - hospital and CCG apportioned cases
Source: PHE, Clostridium difficile infection: annual data

National and local guidance

PHE provides HCAI guidance, data and analysis which monitors the numbers of certain infections that occur in healthcare settings through routine surveillance programmes, and advises on how to prevent and control infection in establishments such as hospitals, care homes and schools.

HCAI Operational guidance (2013) provides the steps health protection teams will need to take to make sure they meet healthcare associated infections (HCAIs) standards.

The Health and Social Care Act 2008: code of practice on the prevention and control of infections and related guidance.

PHE gives information on antimicrobial resistance (AMR), sets out effective methods to avoid unnecessary prescribing of antibiotics and provides advice for healthcare professionals.

Risk factors

Several factors can cause health care-associated infections3. Some of these factors are present regardless of the resources available:

    • prolonged and inappropriate use of invasive devices and antibiotics,
    • high-risk and sophisticated procedures,
    • immuno-suppression and other severe underlying patient conditions,
    • insufficient application of standard and isolation precautions.

Some determinants are more specific to settings with limited resources:

    • inadequate environmental hygienic conditions and waste disposal,
    • poor infrastructure,
    • insufficient equipment,
    • understaffing,
    • overcrowding,
    • poor knowledge and application of basic infection control measures,
    • lack of procedure,
    • lack of knowledge of injection and blood transfusion safety,
    • absence of local and national guidelines and policies.

Antibiotic consumption in England is on the rise and increased antibiotic prescribing is fuelling increased resistance in bacteria. PHE wants to see a reduction in the number of infections caused by antibiotic resistant bacteria4. Antibiotic prescribing and antibiotic resistance are inextricably linked and areas with high levels of antibiotic prescribing also have high levels of resistance.

[1] PHE, Annual Epidemiological Commentary: Mandatory MRSA, MSSA and E. coli bacteraemia and C. difficile infection data, 2014/15, July 2015

 [2] Apportioned cases are assigned to the hospital or CCG when the Post Infection Review (PIR) indicates which organisation is best placed to ensure any lessons learned are actioned.

[3] WHO, Health care associated infections fact sheet, 2011

[4] PHE, Health matters: antimicrobial resistance, December 2015