The latest HCAI prevalence surveys in adult patients were conducted in 2006 in acute hospitals across England, Wales, Northern Ireland and the Republic of Ireland (Smyth et al 2008) and in 2005–2006 in both acute and non-acute hospitals in Scotland (Reilly et al 2008). The results estimate the prevalence of HCAI to be between 7.3 and 9.5%, which means that at any one time approximately one in eight patients could have an HCAI. Infections associated with invasive procedures and the use of medical devices such as intravascular devices and urinary catheters account for a high proportion of HCAI. Prevalence and incidence results in the UK also reiterate the fact that common microorganisms like those that have already been mentioned continue to cause problems.

It had been thought that up to one third of all HCAIs would be preventable by better application of proven methods of prevention (Haley et al 1985, Harbarth et al 2003). However, more recently it has been claimed that certain HCAIs, in particular central venous catheter-related bloodstream infections, could potentially be eliminated (Pronovost et al 2006). The nurse has a crucial role in achieving this, as described in this chapter.

Emerging infections such as Legionnaire’s disease, human immunodeficiency virus (HIV), severe acute respiratory syndrome (SARS) and pandemic influenza also continually pose challenges to public health as well as to health care settings. This necessitates contingency planning both at population level and within organisations, including health care systems. For example, during the 2009 influenza A (H1N1), or ‘swine flu’ pandemic, the extensive planning that had taken place across many parts of the world and within health care systems in the preceding years enabled a rapid response to the situation as it evolved over time. The tremendous increase in world travel over recent years has added to concerns about the threat posed by infectious diseases, many of which can spread rapidly around the world affecting large numbers of people. Whilst in the UK, the long-standing, vaccine-preventable infectious diseases including measles, mumps and rubella (MMR) affect only a small number of people compared to the past, reduced uptake of childhood immunisations such as the MMR vaccine has in recent years resulted in lowered ‘herd’ immunity (immunity across an entire population) and, consequently, an increase in these diseases. Infections familiar only to older generations, for example smallpox, have caused recent concern in an age when there is heightened awareness of the risks from bioterrorism. Governments internationally are preparing both for the re-emergence of diseases that have previously been eradicated or controlled and for the emergence of new diseases, at the same time as attempting to control the common HCAIs occurring in our health care settings.

Less common in the UK, but often with drastic outcomes, are infections spread via the food-borne route. In the past these have had a major impact on both hospital settings and the community. The outbreak of Escherichia coli O157 infection, spread through meat in a butcher’s shop in Wishaw, Lanarkshire, in 1996, resulted in the death of many people within that community and attracted much media interest over hygiene controls in food premises. In hospitals and care facilities, guidance on effective food preparation, production and distribution techniques is vital for effective infection control. The nurse’s role in food hygiene often involves basic measures such as ensuring patients’ own food is in date, stored and reheated correctly. It may also include maintaining correct hygiene procedures relating to enteral feeding systems. Awareness of the importance of food hygiene overall is essential.

Infection prevention and control measures aim to reduce the burden of HCAI and other infectious or communicable diseases, on individuals, health care organisations, and within the National Health Service as a whole. The Health Protection Agency, Health Protection Scotland and Departments of Health in all UK countries coordinate many activities, such as national surveillance and control programmes, in order to highlight and act upon the actual burden in specific settings (see Useful websites, p. 515). Nurses are well placed to contribute to the prevention, control and management of infection within health care settings and beyond. Indeed, nurses occupy a wide diversity of roles, including those concerned with public health, providing ever-increasing opportunities to influence the health protection and patient safety agendas.

For further information about the national burden of HCAI and spread of other infectious diseases, see the recent national prevalence surveys (Reilly et al 2008, Smyth et al 2008), National Audit Office reports (2000, 2004, 2009), the Care Quality Commission’s work, the UK Health Department websites, the Health Protection Agency and Health Protection Scotland websites (see Useful websites, p. 516).

How infection spreads

The terms ‘infection process’, ‘cycle of infection’ and ‘chain of infection’ are often used to describe the circumstances that can lead to patients or others developing an HCAI or any infectious disease. The rationale for applying infection prevention measures is based on this chain of events. It is crucial to understand how microorganisms spread and infection occurs. The infection process involves:

• The presence of an infectious agent, i.e. microorganisms that are capable of causing infection.

• A reservoir or source where microorganisms can be found. Within health care settings, this includes people (i.e. patients, staff and visitors) and also the environment, e.g. dust, bedding, equipment, furniture, sinks, washbowls, commode chairs and surfaces.

• The potential for microorganisms to be transmitted from sources. This is often called a ‘portal of exit’ and is the means by which microorganisms are expelled from the body, such as exhalation, aerosolisation (when liquid droplets are dispersed into the air, e.g. when coughing or sneezing), secretion and excretion.

• A means or route of transmission of microorganisms, categorised as contact, droplet, air-borne, blood-borne, food- and water-borne (common vehicle) and vector-borne.

• The potential for microorganisms to enter the body through a susceptible site. This is often called a ‘portal of entry’ and includes a breach in skin integrity such as a wound or open skin lesion, mucous membranes, ingestion and any breach in normal immune defences (Figure 16.1), commonly through a variety of invasive devices, e.g. intravascular catheters, urinary catheters, respiratory devices.

• A susceptible host – anyone who, for whatever reason, is at risk of infection by microorganisms, including those that would not normally cause them harm. Factors that affect the body’s natural ability to fight infection include:

– the presence of underlying disease, e.g. diabetes mellitus

– being immunocompromised, e.g. HIV infection, chemotherapy treatment

– poor nutritional status

– extremes of age, i.e. the very young and the very old.

Figure 16.1 Barriers to infection.

The principles relating to all infection prevention measures are based on the interruption of this process. If these measures are not taken, a cycle will continue whereby patients, and possibly staff and others, may be exposed to potentially pathogenic (disease-causing) microorganisms that can cause harm.

Microbiology

Microbiology is the study of microorganisms and other causes of infection, including bacteria, viruses, fungi, protozoa, prions and helminths.

Bacteria

Bacteria, including variations of the microscopic beings such as mycoplasmas, rickettsiae and chlamydiae, are small microorganisms of simple primitive form. Bacteria are commonly found living within the human body and in the environment, for example in soil and water. Those species of bacteria capable of causing disease in humans are known as ‘pathogens’. Some are more ‘pathogenic’ than others. Most are acquired though contact with other people or the environment (i.e. ‘exogenous’ sources). Table 16.1 gives some examples of pathogenic bacteria commonly encountered while providing health care. Bacteria that constitute the normal commensal flora within the body are not normally pathogenic (Table 16.2). However, in certain situations, such as when these bacteria gain access to a different anatomical location within the body, they can cause disease. This is known as ‘endogenous’ infection. It is not always clear when infections are exogenous or endogenous.

Table 16.1 Examples of common bacteria encountered while providing health care

Table 16.2 Normal commensal microorganisms

Site	Organism
Skin	Staphylococcus epidermidis
	Diphtheroids
	Corynebacterium sp.
Mouth and throat	Staphylococci
	Streptococci
	Anaerobes
	Neisseria sp.
Nose	Staphylococci
Nose	Diphtheroids
Gut	Escherichia coli
	Klebsiella sp.
	Proteus sp.
	Streptococcus faecalis
	Clostridium perfringens
	Yeasts (Candida)
Kidneys and bladder	Normally sterile
Vagina	Lactobacilli
	Streptococci
	Staphylococci
	Anaerobes

The infection prevention team

Health care workers, patients, relatives and carers together have a contribution to make in the prevention, control and management of the spread of infection. Those involved include nurses, doctors and dentists, allied health professionals, microbiology laboratory scientists, health care assistants, domestic and catering services, estates management, sterile services staff, administrative and management staff, education and training staff.

The role of the infection prevention team (IPT) has been defined and includes the utilisation of the risk management approach (see p. 505), provision of relevant specialist advice, ensuring appropriate measures and action plans are in place and supporting sustained improvement through a change of culture throughout their health care organisation. The team has clear accountability for reporting infection prevention and control progress and issues through relevant management structures, such as clinical governance and patient safety committees and, at times, directly to chief executives. The infection prevention doctor (IPD) and infection prevention nurse (IPN) have clear responsibilities within the health care organisation. More recently, leadership and management roles, including the Nurse Consultant, Director of Infection Prevention and Control (in England and Wales) and Infection Control Manager (in Scotland) have added to the structure.

Other recent additions to the IPT include audit and surveillance staff amongst other invaluable support staff. Whilst in secondary care settings this arrangement is generally well established, this is not always so within primary care, where the community-based IPT may be a relatively new addition, yet provide a vital service, both for commissioning and provision of specialist services. The role of the health protection nurse working at regional or national level may also be a relatively new contact for infection prevention and control teams, but provides an important link as part of the strategic infection prevention work within a locality and nationally.

Many settings also have infection prevention link personnel to enhance the effectiveness of the work of the team. The link person in a ward, department or community team receives additional education to improve the communication between infection prevention and control teams and the clinical setting and may assist with clinical audit and awareness of clinical staff in relation to Standard Precautions (see p. 507).

The work of the infection prevention team is guided by the Control of Infection Committee, which is responsible for strategic and operational decisions about infection prevention and control within a given organisation or, in the case of the community, across a locality. However, the IPT also reports to clinical governance, risk management and patient safety committees to ensure action and effective cross-facility outcomes. The outcomes for infection prevention programmes of work at organisation level, as led by teams, are guided by national and local requirements and needs.

The nurse’s role in infection prevention

Nurses can contribute to all aspects of infection prevention in clinical practice, acting as role models and educating others. Nurses have a pivotal role in managing infection in acute and primary care settings by:

• maintaining up-to-date knowledge and high standards of clinical practice based on best available evidence, including training and educating clinical colleagues

• reporting and acting upon incidents when it has not been possible to implement best practice

• assessing infection risks to patients, staff and others and identifying the actions required to minimise them

• promptly identifying signs and symptoms of infection and taking the appropriate actions (e.g. referral to a medical practitioner, collection of a clinical specimen)

• seeking specialist advice for support with risk assessment when required

• involvement in the promotion of messages about best practice and monitoring standards of infection prevention

• educating patients and their carers about infection prevention measures.

Nurses in the UK have a duty of care as stated in the Health and Safety at Work Act (1974) to prevent, control and manage infection. Nurses, as the largest staff group in health care, have a responsibility to deliver care based on the best available evidence or best practice (Nursing and Midwifery Council [NMC] 2008). This includes preventing the spread of infection, ensuring they do not put themselves and others at unnecessary risk from infection. In England and Wales, The Health and Social Care Act (DH 2008, p. 2) requires health care professionals to ‘demonstrate good infection control and hygiene practice’.

Nursing assessment is vital to health and infection prevention, whether the health care setting is the home, the hospital, the clinic or the care home, as it can reveal crucial information about patients, their surroundings and their behaviours. Nursing models and processes must incorporate approaches to prevention, control and management of infection, for example, within care plans and pathways.

The health of nurses while at work is also important. Nurses should:

• stay away from work if unwell, particularly if the illness could be communicated to others, e.g. influenza, infection with the Group A streptococcus, or Streptococcus pyogenes (particularly in the throat)

• be aware of their own immunity to infectious diseases such as rubella, chickenpox, measles, tetanus and hepatitis B; nurses can obtain advice from their general practitioner (GP) or from their employer’s occupational health department

• discuss other health concerns that may have an impact upon the ability to work, or upon others, with the Occupational Health Department, e.g. allergies that may be caused by supplies used during work and skin conditions that may harbour and spread microorganisms.