The body is made up of many different tiny cells, like a machine that has lots of small parts which work together. Bacteria are even smaller than cells. Bacteria are found in lots of different places:

• soil
• food
• water
• rock
• in the body
• in the home
• many others

Some of them are bad bacteria and these cause disease and illness, stopping the body from working properly. Bad bacteria do this either by hurting the cells from the outside or infecting the cells. They act like rust damaging the machine from the outside or bits of dirt and rubble which can get into machines and stop them from working. There are also good bacteria which act like oil in machines and help the body to work. They do this by taking the food and space in the body so that the bad bacteria cannot live.
Good bacteria live inside the body all the time and help to fight illness. Bad bacteria are not found very often inside of the body. When they do get inside and manage to live and grow, the body tries to get rid of them. This is done naturally by special cells called immune cells. Immune cells act like small soldiers in the body to fight bad bacteria, viruses and fungi. They kill the bacteria and do not let them spread in the body. Immune cells also remember the types of bacteria that they have fought. If they find the same disease in the body again, they quickly attack the bacteria. This stops the bacteria before they can harm the body.

Sometimes the immune cells cannot kill the bacteria. Bacteria can have in built shields to protect them. Other bacteria can hide in the body, away from the immune cells. Both of these types of bacteria can live in the body and can cause illness. When people become sick with these bacteria, doctors can give people antibiotics to help. These are special medicines that only work against bacteria to kill them or stop them from growing. If they stop the bacteria’s growth then immune cells can come and attack the bacteria.
Antibiotics are really important when fighting bacteria but bacteria are making plans to combat them. The more that antibiotics are used, the more time that bacteria can have to create defences against them. Some of the protections against the antibiotics are so good that some antibiotics do not work anymore. Now antibiotics are being used carefully and doctors have to work out when they are best to be used. This makes sure that the bacteria cannot change and protect themselves against the medicines.
There are many illnesses that are caused by bacteria. Some of them are more dangerous than others:

• Escherichia coli. Some types of this bacteria are good and live in the stomach. There are also bad types that can cause diarrhoea.
• Mycobacterium tuberculosis (TB). This can cause severe coughs, fever, night sweats, weight-loss and coughing up blood.
• Salmonella typhi, causing typhoid which gives the person high fever, weakness, stomach pain, constipation and sometimes red spots on the skin.
• Neisseria meningitidis which causes meningitis. This can lead to tiredness, fever, headaches and in very bad cases neck stiffness and death.
• Vibrio cholerae, causing cholera. This mainly causes watery diarrhoea and sometimes vomiting and muscle cramps.
• Shigella, normally causing dysentery which is bloody diarrhoea as well as fever

If you think you may be ill with these bacteria, find medical help as soon as you can.