Karen Foggon
Causes and spread of infection
Unit reference H501/7103
Understand the causes of infection
LO!
1.1 And 1.2.
See unit 9 lo 4.2
HCAI’s have been on the rise and certainly focused on by both local and national press. The pathogens and infections are outlined below:
Bacteria are single celled organisms, and are shaped like rods spheres or spirals; they reproduce by dividing and can multiply quickly in the body. Less than 1% of all bacteria are harmful. Harmless bacteria live in our bodies and help digestion and provide nutrients and can destroy some disease causing organisms. The disease causing bacteria produce toxins that damage cells and make you ill. Antibiotics are the main form of treatment, but there are antibiotic resistant strains emerging. Common bacterial infections are:
MRSA
Clostridium difficile
E-coli
Impetigo and boils
Diarrhoea
Salmonella
UTI’s.
Viruses are smaller than cells and are just a capsule that contains genetic material DNA or RNA. A virus is not a living organism and needs a living host otherwise it cannot survive. In order to reproduce they invade cells in the body and alter or take over the cells function. Common virus infections are
Influenza
Warts
Chicken pox
Herpes
Common cold
Gastroenteritis.
Hepatitis B
See page 9
Fungi are a parasitic plant that includes moulds mildew and yeast. A fungal infection is an inflammatory condition in which fungi multiply and invade the skin, digestive tract genitals lungs and liver and other tissues. A few can lead to quite serious illness but in the main cause mild infections. Fungi like dark damp places or skin that is irritated, weakened or constantly damp. In order to survive they live off dead tissue hair and nails. Fungal infections includes
Athletes foot Thrush
Candida
Nail infections
Ringworm

Parasites are organisms that need to live inside humans or other organisms to act as hosts as they are unable to produce food or energy themselves. They eat away body tissue and cells and produce a toxic waste that makes people sick. The main types of parasites are
Intestinal worms that be seen with the naked eye,
Small parasites such as amoebae usually stay in the intestines but can migrate to anywhere in the body, vital organs the brain and bloodstream.
Head lice
1.3
We are all covered by a range of bacteria known as body flora and can give protection to unbroken skin. Staphylococcus aurous and Staphylococcus epidermis are the two common ones. Once the skin is broken these and others can enter the body. Colonisation is the presence of multiplying bacteria in a wound, with no immune response, no active disease or ill health. It is a normal state with no delays in wound healing. Infection is multiplying bacteria that overwhelm the immune system resulting in spreading cellulitis, increasing pain and wound breakdown, and delays wound healing.
1.4
A localised infection is where it is restricted to the area that it entered, and can cause symptoms such as pain, pus redness oedema and skin that is warm to the touch. Systemic infection is one that affects the whole body most likely through blood, and can be life threatening if left untreated examples are septicaemia, Sepsis and blood poisoning
1.5
Infection requires a source, mode of transmission and a host. He main means of transmission are air bourn, droplet and contact, so if universal precautions are not followed then any infection will spread. The main poor practices in the spread of infection are:
Poor hand hygiene, not washing hands properly or at all. Not washing between patients etc. see unit 9 lo 6.4 failure to use and dispose of PPE
Poor Housekeeping, not disposing of waste appropriately
Poor aseptic technique
Failure to recognise and report infectious outbreaks.

LO.2 Understand the transmission of infection
2.1
Microorganisms need both chemical and physical elements to enable them grow. They need water and mineral