Bacteria are single-cell organisms, they are living things that belong to a group of their own, and therefore they are not classed as animals or plants. They are usually only a few mm in length, can be spherical, rod or spiral shaped, contain a cell wall and normally exist together in millions. Bacteria can only reproduce asexually and does not contain a nucleus. Bacteria can be beneficial, but it can also be pathogenic (cause disease in humans). Examples of diseases caused by bacteria: Sexually Transmitted Infections Pneumonia Gastritis Urinary Tract Infection.
Food Poisoning Upper Respiratory Tract Infection Sinusitis Skin Infections Staph Infection Fungi Fungus is a plant like organism that has its own kingdom, is normally found as a single cell and includes yeast and mould. Fungi has a variety of shapes and sizes and reproduce via spores, this can be sexually or asexually. Fungi can be beneficial and pathogenic, but is generally a concern of decomposition in food. Fungi only respond to the treatment of antifungal drugs and will not be affected by antibiotics. Examples of diseases caused by fungi: Athlete’s Foot.
Ringworm Otomycosis (thrush of the ear) Fungal Infections of the Skin Virus A virus is a complex molecule of proteins and genetic material but is not a living cell; it doesn’t have its own cell structure and can be found in the environment, water and air. It is the smallest type of microbe; too small to be seen directly or with a light microscope, and measure at 20-200 nanometres – 35x smaller than a human red blood cell and 1/100 the size of standard bacteria and do not contain the same protective layers that bacteria have – cell wall and energy production.
Unlike bacteria, viruses need a living host and food to replicate; they do this by entering the cell of the host and taking over the genetic material responsible for reproduction, they can then produce more copies of the virus. They can infect all living things including plants, animals, and the living cells and tissues within human beings being transported via droplet, sexual, fecal and parenteral contact, and they don’t reproduce in the food. Viruses are usually harmful and target specific cells in the body such as those in the upper respiratory tract and genitals.
Some viruses such as croup target certain age groups like babies and young people. Some viral infections can be systematic – meaning that they affect many different part of the body at once e. g. runny nose, cough, achy body, some can be local – a viral infection with pain in one place that can trigger itching and burning e. g. viral conjunctivitis, and they are treated by antiviral drugs. Examples of diseases causes by viruses Cold’s Influenza Chicken Pox Cold Sores Herpes Hepatitis A.
Norovirus Parasites Parasites are a multi-celled organism classed as animals. They are usually bigger than a bacteria and can easily be seen under a microscope, sometimes even by eye. Parasites need a living host to complete their life-cycle, unlike bacteria, and are generally host specific commonly found in soil, water, air and animals. Parasites are most commonly transmitted through consumption of contaminated food and drink, and can also be passed through contact with a contaminated surface.
Examples of diseases caused by parasites: Malaria River Blindness Sleeping Sickness Lyme Disease Scabies Tapeworm Trichinosis 1. 3. Infection Infection can be defined as harm caused by a micro-organism, invasion of the body by pathogenic organisms or the pathological state resulting from having been infected. If a human has an infection they are known as the host, this means that there is another germ known as a parasitic organism inside them colonises and reproduces.
The parasitic organism uses the host to feed on and multiply to such an extent that it affects the person’s health. Colonisation Colonisation can be defined as the ability of some micro-organisms to live in or on a host without causing disease, the presence and multiplication of micro-organisms without tissue invasion or damage. The colonies develop when the bacteria cell begins reproducing, or the development of a bacterial infection on an individual, as demonstrated by a positive culture.
The infected person may have no signs or symptoms of infection while still having the potential to infect others. Colonisation is when microorganisms occupy a specific part of the body without causing signs and symptoms of infection, although they do have the ability to cause infection if they spread to another part of the body or onto another person. Colonised pathogens can be transmitted via person to person contact or by the passing of objects. 1. 4. Systematic Infection.
A Systematic Infection is an infection that can affect the whole body or multiple organs, usually travelling in lymph or blood. An example of a systematic infection is septicaemia. Localised Infection A localised infection is a collection of infected tissue that is maintained within one area, the area where the infection entered the body e. g. a small wound. If infected tissue breaks away from the original site of infection and travels to other parts of the body it becomes a systematic infection. 1. 5.
Examples of poor practice: poor hand hygiene incorrect use of PPE insufficient cleaning and decontamination of setting and equipment poor waste disposal and storage procedures 2. 1. Conditions needed for the growth of micro-organisms are: Moisture – to carry foods in solution away from the cell, wastes in solution away from the cell and to maintain the moisture content of the cytoplasm. Nutrients – to provide bacteria with sufficient quantity of the correct food which allow them to grow and multiply.
Warmth – the speed in which bacteria grow depends on the temperature. Bacteria multiply rapidly in warm temperatures and die or become unable to multiply under temperatures that are too cold. Time – bacteria needs time to reproduce. 2. 2. An active agent may enter the body: By entering the nose or windpipe and travelling into the lungs e. g. coughs, colds, influenza. By entering a break in the skin or mucous membrane that lines the nose and mouth, usually bites, scratches, needle puncture wounds etc.
By entering the mouth – infected food or drink can be swallowed, travel down the digestive tract into the stomach and intestines. This causes an infection in the stomach or bowel and presents itself in the form of sickness and diarrhoea. Via sexual transmission the agent may enter into the bloodstream and colonise e. g. HIV, AIDS. Sexually transmitted infections can also remain localised e. g. Genital warts. 2. 3. Common sources of infection are people, contaminated laundry, contaminated food, clinical waste, contaminated equipment and dust. 2. 4.
Infective agents can be transmitted to a person via direct contact e. g. hands and equipment, or indirect contact e. g. the environment. 2. 5. Key factors that make it more likely that infection will occur: Age (babies, children and the elderly people are more prone to infection) A weakened immune system (certain illnesses such as cancer, or medicines such as immune suppressants for the treatment of chrones disease can cause a weakened immune system) Long term anti-biotic therapy Exposure to infectious agents A Lack of safety precautions Poor hygiene.