To begin to understand why we must undertake infection control measures we must first consider aspects of microbiology. Microbiology is broadly described as the study of bacteria, fungi, protozoa, viruses, and helminths. We share our world, including our bodies, with millions of microscopic organisms and we need to understand how best we can live with them. In studying these groups of organisms, including their many subgroups and families, we can learn how:

• they live within us;

• they live in our environment;

• they can cause harm; and

• we can treat infections caused by them.

Within healthcare settings, many microorganisms have the perfect living and breeding conditions, due to the numbers of susceptible patients gathered in an ideal environment. For examples of common microorganisms found in healthcare settings, see Appendix 1. Now carry out Learning Activity 1

Cycle of infection

The term cycle of infection is used to describe the processes leading to patients acquiring infection within healthcare settings. Knowledge of this cycle is essential in order to understand how infection can occur. All precautions and measures taken in order to prevent and control infection are based on the interruption of this cycle