Healthcare associated infections
February 2006
Nature of the problem
There is no single cause for the increase in HCAIs in the UK; however, a number of factors contribute to the problem including:
1. Patient susceptibility
With the development of new treatments and improvement in traditional treatments, many more seriously ill patients are being treated. The degree of underlying illness in patients has been identified as one of the two strongest risk factors linked to HCAIs. [Go to note 1] Patients with weaker immune systems are particularly at risk. This includes the very young and very old, patients in intensive care units and patients undergoing complex treatment or surgery – such as transplant or chemotherapy patients – that suppress their immune system.
2. Therapeutic interventions
The second of the two strongest risk factors linked to HCAIs has been identified as the use of medical devices such as catheters, tubes, drains and feeding lines. Their insertion breaches the body’s natural defences and creates a pathway for micro-organisms to enter a patient’s system. Risk of infection is increased the longer such devices dwell in a patient and where best practice in terms of hygiene and device management is not followed. Another major concern is the level of surgical site infections (SSIs) that are caused during, before or after surgical procedures. Complex surgery increases the vulnerability of patients as well as the length of time spent in hospital. SSI are caused by organisms on the patient’s own skin, organisms on the skin or clothing of operating theatre staff, organisms in the environment at the time of operation, operating on a contaminated site (eg bowel), incompletely sterilised surgical instruments, and unhygienic wound care in the post-operative period. Approximately 10 per cent of all HAIs are surgical site infections and these are estimated to result on average in an additional six and a half days hospital stay. [Go to note 17] A report summarising the findings of a voluntary SSI surveillance system in hospitals in England between 1997 and 2002 found that 49 per cent of SSI were caused by Staphylococci, and that 81 per cent of these were S.aureus, of which 63 per cent were methicillin-resistant. [Go to note 18] With short hospital stays, many surgical site infections do not become evident until discharge into the community.
3. Behaviour of healthcare professionals
Micro-organisms are commonly transmitted by staff, from one patient to another or from the environment to the patient. Failure of healthcare professionals to decontaminate their hands adequately between patients has been shown to contribute to the spread of infection. [Go to note 1] Despite this, compliance with hand hygiene protocols among healthcare professionals is poor, thereby increasing the risk of cross-contamination. [Go to note 19] Compliance levels vary significantly and it is difficult to determine the exact impact on the spread of HCAIs. Non-compliance results from a lack of understanding of the associated risks, a lack of knowledge of the guidelines, inadequate hand-washing facilities, time pressures, inadequate access to hand hygiene agents, and the irritation caused by hand hygiene agents. [Go to note 1]
4. Environmental factors
Micro-organisms that cause infection enter the healthcare system in many different, often unavoidable ways. If the healthcare environment is not cleaned thoroughly and procedures to ensure that instruments, beds and all other appliances are disinfected are not followed then the risk of infection is greatly increased. A poor level of cleanliness of instruments, floors and walls in clinical areas is one of the factors that may contribute to the spread of HCAIs. [Go to note 2] In 2005, the Healthcare Commission carried out a brief audit of hospital cleanliness and infection control, consisting of unannounced inspections of a sample of acute, community and mental health hospitals, in both the NHS and independent sectors in England. The results of the audit found that a third of hospitals visited (33 out of 98) achieved the highest standards of cleanliness, while 43 of the 98 hospitals failed to perform as well as they could. [Go to note 20] There was clear evidence of systemic problems with cleanliness in 22 of the 98 hospitals, indicating that cleanliness was unsatisfactory for an environment in which clinical care is being provided. [Go to note 20] Overall, the standards were found to be markedly poorer in mental health hospitals compared to acute hospitals. The Commission plans to use the collected information to carry out further inspections of the hospitals rated as performing poorly and will emphasise cleanliness as a priority in its inspections under the new annual health check for NHS organisations. A more detailed longer-term study of HCAIs is due to be undertaken in 2006. Further information can be found on the Healthcare Commission review website at here at www.healthcarecommission.org.uk
5. Organisational factors
The risk of HCAIs is greatly increased by extensive movement of patients within the hospital and by very high bed occupancy. Improved medical knowledge and technology, and increasing patient throughput puts significant pressure on infection control teams that are often under-resourced and over-stretched. These factors create poor healthcare staff-to-patient ratios and mix patients with a wide range of serious illnesses from a large geographical area, thereby facilitating the spread of infection.
6. Estates and facilities
At present, many healthcare institutions are operating with insufficient isolation facilities including single-bed rooms and isolation wards, and inadequate numbers of hand-washing stations or access points providing disinfectant agents such as alcohol wipes.2, 3 An improved local infrastructure is required to control the spread of HCAIs and increase the likelihood of compliance with hygiene protocols.
7. Antimicrobial resistance
Antimicrobial resistance and multi-resistant micro-organisms make HCAIs more difficult to treat, inhibit recovery after surgical interventions, increase the length and severity of illness, prolong the period of infectiousness, and lengthen hospital admissions and costs. Antimicrobial treatment is an essential component of modern healthcare. The indiscriminate and inappropriate use of antimicrobials in medicine and agriculture promotes the emergence of antimicrobial resistance and multi-resistant micro-organisms.