INTRODUCTION

Great importance must be put on the maintenance of a safe and clean clinical environment for the patients. Within the diagnostic imaging department it should be recognised that all patients have the potential to carry and transmit organisms. It has been shown that nosocomial infections (those occurring in a hospital setting) can be reduced considerably with the introduction of basic hygiene procedures.¹ In order to prevent the transfer of infections it is important to be aware of the specific organisms that can cause infection and the mode of transfer so that the cycle of replication can be disrupted.

DISEASES AND ORGANISMS

A disease is a condition causing symptoms of an illness, which occurs when cells or molecules within the body stop functioning properly. For example, a disease can be caused through aging, the effects of chemicals, or arise from gene mutation/alteration.

There are four main groups of pathogenic organism which can cause diseases, some of which are harmless to the host when sited in the correct place; for example there are organisms living in the bowel which cause infection when they enter the urinary or respiratory tracts.

CROSS-INFECTION

An infection occurs when other organisms, e.g. bacteria, viruses, fungi or protozoa, enter or come into contact with the body and multiply. The organisms can cause direct damage or prompt an immune response, which causes symptoms to manifest, e.g. fever.

Infections can be:

The cross transfer of a pathogenic organism from one individual to another (cross-infection) can occur in the following ways:

Therefore, it is essential that the equipment, environment and healthcare professional are subject to varying levels of cleanliness dependent on the clinical requirement (Table 5.1). There arethree main levels of cleanliness that exist with regards to equipment and surfaces: clean, disinfected and sterilised.

Table 5.1 The purpose and contraindications of cleansing agents

Cleaning agents	Purpose in department	Contraindications for use
Chlorhexidine gluconate solution 2.5%	For cleansing the skin prior to a procedure	Not for hard surfaces
Chlorhexidine gluconate 0.015%, cetrimide 0.15% (e.g. Savlon/Tisept/Sterets)	Pre-injection Skin sterilisation Bottle tops

Not for hard surfaces or open wounds Chlorhexidine gluconate solution 2.5% (e.g Hibiscrub) None Detergent, sanitiser, blue bleach powder (sodium hypochlorite) For body fluids and spillages Not for skin Cleansing foam (e.g. Esemtan) Antimicrobial deodorising foam Not for hard surfaces, floors, etc. Povidone iodine 7.5% (e.g. Videne antiseptic solution) A rapid acting non-irritating aqueous iodine solution For skin only. Not for hard surfaces, floors, etc. Alcohol impregnated wipes For hard surfaces and skin Not for open wounds Sodium chloride 0.9% solution For skin and open wounds None ‘Decon’ For neutralising radioactive spills None