37. Principles of hospital infection control

Questions

What are the principles and role of surveillance in infection control?

Give three different examples of how to control nosocomial infections.

Hospitalized patients are more likely to develop infections as a result of invasive procedures (e.g. surgery), use of medical devices (e.g. intravascular catheters) and impaired host defences through underlying diseases, treatment or extremes of age. A breakdown in infection control practices increases the spread of typical hospital microorganism such as methicillin-resistant Staphylococcus aureus (MRSA), Clostridium difficile and norovirus.

In England, the prevalence of hospital-acquired infection (HAI; nosocomial) in 2006 was 8.2%. These infections (Fig. 3.37.1) increase patient’s morbidity, mortality, length of stay and add to the economic burden. It is estimated that approximately 5000 patients die as a result of HAIs in the UK each year.

Fig. 3.37.1 Main hospital-acquired infections.

Sources of infection

HAIs are infections acquired in hospital that were not incubating or present at admission. Exogenous infections are ones where the source of infection is the environment (e.g. via contaminated food, fluids, equipment and air) or through cross-infection from staff, visitors or other patients. Endogenous infections are where the pathogens causing infections are acquired from the patient’s own microflora (e.g. vascular line sepsis from common skin bacteria). The sources of HAIs and common causative pathogens are shown in Fig. 3.37.2.

Fig. 3.37.2 Common source of hospital infections and associated pathogens. MRSA, methicillin-resistant Staphylococcus aureus.