HOSPITAL ACQUIRED INFECTION
Patients admitted to hospital have always been
at increased risk of acquiring new infections. This has been an
inevitable consequence of housing a population of susceptible
individuals in close proximity, the transmissibility of micro-organisms,
and the result of medical and surgical interventions that impair
the normal human barriers to infection. In the nineteenth century
more than 50 per cent of patients undergoing surgery in major
British hospitals died of a post operative infection. In the last
hundred years improved hygiene (including aseptic practices and
sterilisation techniques) and the introduction of antibiotics
have improved matters dramatically; however, hospital acquired
infection continues to provide a major burden of disease. It has
been estimated that about nine per cent of inpatients in the UK
have a hospital acquired infection (HAI) at any one time, equivalent
to at least 100,000 infections a year. Based upon extrapolations
from US data, around one per cent of all deaths in the UK have
been attributable to hospital acquired infection (approximately
5,000) and around three per cent (15,000) where hospital acquired
infection is a contributory factor. Associated costs are substantial.
These relate to increased lengths of stay, treatment costs, and
socio-economic losses, and probably amount to more than £1,000
A number of new challenges have contributed
to the continued importance of HAIs. These include the increased
use of intensive care and invasive procedures; more extensive
use of indwelling devices and prostheses; greater and more aggressive
use of immuno-suppressive drugs; improved survival of vulnerable
patients; more intensive use of hospital facilities; and the emergence
of highly antibiotic resistance and transmissible micro-organisms
such as Methicillin Resistant Staphylococcus aureus (MRSA).
Resistant infections are more difficult to treat resulting in
increases in length and severity of illnesses, adverse reactions
(due to the need to use less safe drugs), and costs.
Evidence derived from the Nosocomial Infection
National Surveillance Scheme (NINSS) operated by the PHLS on behalf
of the NHS suggests that the incidence of HAIs may differ from
hospital to hospital. The reasons for such variations are as yet
unclear and probably multi-factorial. However, in some cases they
are likely to represent different levels of infection control
performance providing the population with a variable risk of HAI
depending on where they live in the hospital they attend. It also
suggests potential for improvement.
HAIs cannot be prevented completely. The proportion
that is avoidable is unclear. The Department of Health/PHLS Hospital
Infection Working Group indicated that it might have been possible
to achieve a 30 per cent reduction. On the basis of a census of
infection control teams (ICTs) the recently published National
Audit Office report suggested 15 per cent. This would represent
a saving of at least 750 lives and £150 million annually.
If current infection prevention and control
arrangements (including measures to limit antibiotic resistance)
are not developed and enhanced, it is likely that the health and
financial burdens associated with HAIs will increase. This will
result particularly from an inevitable rise in antibiotic resistance
related problems and increasing numbers of vulnerable patients
with chronic conditions, many of which result in decreased immunity,
staying in hospital.
The key individuals responsible for implementing
and maintaining good practice in relation to the prevention and
control of HAIs are the many health care staff whose work brings
them into direct contact with patients or whose duties have a
direct bearing on reducing risk (eg engineers, cleaners and staff
involved in sterilising equipment and instruments). Hospital infection
control teams comprising specialist medical and nursing staff
play a vital role in: collection and analysis of data relating
to the occurrence of HAIs; formulation of policies, and their
development and dissemination; providing expert advice; undertaking
education and training; monitoring and audit of hospital hygiene;
and clinical audit. Ultimate managerial responsibility in hospital
trusts lies with the chief executive. Primary care groups or trusts,
health authorities, regional offices and central government discharge
varying responsibilities at different levels. Local authorities
have statutory duties in relation to communicable disease control
within their boundaries. They usually take a direct involvement
in outbreaks involving food or communicable diseases that have
major implications for the community.
The PHLS plays a major role in undertaking,
supporting and guiding HAI prevention and control at local, regional
and national levels. The functions can be summarised as follows:
provision of diagnostic facilities
for local hospitals complemented by specialist and reference microbiology
at regional and national level;
leadership of hospital infection
control teams. Infection Control Nurses are also PHLS employees
in some trusts;
provision of expert advice locally,
regionally and nationally;
development, implementation and support
of systems for routine and enhanced surveillance ("alert
organism" eg MRSA, targeted clinical surveillance NINSS and
identification and promulgation of
good practice and effective quality and monitoring measures;
contribution to risk identification,
management and reduction;
identification of effective interventions
and facilitation of multi-centre intervention trials;
contribution to training and education
in areas relating to hospital infection control; and
to inform and influence the formulation
of health policy in this area.
Although the situation is improving, there remains
insufficient engagement of trust chief executives and other senior
management staff in dealing with this important issue. This is
reflected in the inadequate resources often made available to
ICTs and their frequent lack of involvement in trust decisions
relating to external contracts and estates issues. It also probably
makes a major contribution to the most important problem, the
variable commitment of clinical staff to adherence to infection
control policies and best practice.
The evidence base for infection control activities
is also lacking. This deficiency includes: scientific data to
guide practices and policies; surveillance and audit information
to measure performance, and health economic analyses to assist
decision making with regard to resource allocation.
Clear direction and target setting in relation
to performance standards and controls assurances from central
government. This has been initiated.
Engagement of chief executives in target setting
for health improvement programmes relating to this area.
Clear direction from chief executives to encourage
involvement and ownership of hospital prevention and control by
Ensure ICTs are provided with adequate resources.
There is a common requirement for improved clerical and IT support.
Provision of cost effective surveillance systems
that offer tools that can give a comprehensive measure of performance
that is comparable with other units and can identify areas that
warrant intervention or further investigation. The development
and adaptation of NINSS will be designed to do this. NINSS will
also be an integral component of a broader surveillance strategy
developed by the PHLS that incorporates laboratory ("Alert
organism") and outbreak based systems.
Agreement for a national surveillance strategy.
Provision of audit tools to complement surveillance.
These will be developed by the PHLS in partnership with others
as a component of their surveillance strategy.
Improved hospital information management systems
to facilitate data collection.
Full involvement of clinical teams in surveillance
and audit programmes.
Development of evidence based guidelines. The
`EPIC' project will contribute substantially to this. It will
also highlight many areas where further research and development
Investment in research and development. Information
regarding effective interventions and improved surveillance methodology
is particularly needed.
Provision of improved support for surveillance,
interventions, education and dissemination at regional level.
The Regional Epidemiologists would be good focus for this activity.
Hospital acquired infection is currently providing
a substantial load of avoidable ill health, mortality and cost
in the UK. Success in reducing this disease burden will depend
critically on leadership and co-ordination across a wide range
of agencies and individuals at all organisational levels dealing
with health care provision. The breadth of the involvement of
the PHLS in this area of activity, from provision of local hospital
infection control services to national surveillance, places the
PHLS in a unique position to guide and support the NHS in England
and Wales to deal with this problem.
Prepared by Drs Tony Howard and Noel Gill, Public
Health Laboratory Services.