What are bacteria?
Bacteria are single-celled organisms that have the ability to reproduce, and feed themselves. Bacteria are found everywhere, including the air, water, and soil. Most bacteria are beneficial for our health and the health of earth’s ecosystems, with only 1% of bacteria causing diseases.
They divide and multiply very quickly. One cell can become 1 million cells in a few hours. Bacteria are about 1000 nm in size, which means they are visible under a light microscope.
How are bacteria treated?
Bacteria can be treated with antibiotics. Some bacterial infections get better with no antibiotics. Your immune system deals with them and you get better.
Examples of bacteria (and the infection they cause)
Bordetella pertussis. This is the cause of whooping cough (also known as ‘pertussis’), and is a very contagious respiratory illness.
Clostridioides difficile (‘C. diff’) – a type of bacteria in your intestines that’s normally harmless. However, using antibiotics or having an weakened immune system can cause overgrowth of these bacteria. This leads to a GI infection characterised by an inflamed colon and diarrhoea.
Corynebacterium diphtheriae. Diphtheria is an infection caused by this bacterium
Escherichia coli (‘E. coli’). This is the commonest cause of UTIs.
Heliobacter pylori (‘H. pylori’) – causes stomach ulcers and chronic gastritis (inflammation of the stomach).
Legionella pneumophila. This causes ‘Legionnaires’ Disease’ (often a pneumonia). The most common form of transmission is from contaminated water; especially related to air conditioning and water systems (e.g. swimming pools and spas).
Methicillin-resistant staphylococcus aureus (MRSA). This is a bacteria that is resistant to common antibiotics like penicillin, amoxicillin and methicillin. Outside of healthcare facilities, MRSA is often harmless or causes a skin infection. Inside healthcare facilities, MRSA infections can be are serious and may lead to death.
Mycobacterium tuberculosis. Tuberculosis is a contagious disease caused by the Mycobacterium tuberculosis bacteria. It usually leads to long term lung infection.
Neisseria meningitidis. This is often referred to as ‘meningococcus’, is a bacterium that can cause meningitis.
Neisseria gonorrhoeae. The bacterium causes gonorrhoea, which is a sexually transmitted disease (STD).
Salmonellae – are causes of gastroenteritis (that can be ‘food poisoning’). They live in the gastrointestinal tracts (GI) of humans and other animals. Symptoms include abdominal pain, diarrhoea and vomiting.
Staphylococcus aureus (or ‘staph’) – is a type of bacteria found on human skin, in the nose, armpit and groin. They usually don’t cause harm, but can make you sick under the right circumstances. For example, S. aureus is a common cause of skin and soft tissue infections, such as abscesses and cellulitis.
Cellulitis
It can also cause more serious infections, such as pneumonia, endocarditis (infection of the heart valves), and bone and joint infections.
Streptococcus pneumoniae. Bacterial pneumonia is a lung infection that can be caused by different kinds of bacteria, like this Streptococcus. Other bacteriae include Haemophilus influenzae, Klebsiella pneumoniae, or Pseudomonas aeruginosa.
Streptococcus pyogenes (or ‘Strep A’). This is the bacterium that causes ‘strep throat’. It can cause other infections including scarlet fever, impetigo and rheumatic fever.
Treponema pallidum. Syphilis is a sexually transmitted disease (STD) caused by this bacterium.
