What are antibiotics and when are they used
Antibiotics are used to treat or prevent certain types of bacterial infections. They work in two main ways, by killing bacteria and to prevent bacteria from reproducing and spreading.
Our white blood cells recognise and attack harmful bacteria and even if symptoms develop, our immune system will normally clear most mild bacterial infections without the need for intervention with antibiotics.
In some cases, however, when an infection is difficult to clear, antibiotics may be used. This includes bacterial infections that:
- are unlikely to clear up without treatment
- pose a risk of infecting others
- evidence suggests the recovery time can be significantly reduced, such as a kidney infection
- may result in developing more serious complications
Antibiotics may also be used as a precautionary measure when someone is at greater risk of acquiring an infection, this may include:
- people over the age of 75
- new born babies, less than 72 hours old, with a proven bacterial infection or at a higher than average risk of acquiring one
- people who are diabetic and take insulin
- people with a weakened immune system due to an underlying health condition such as HIV (human immunodeficiency virus), or as a side effect of other medical treatments such as chemotherapy
- after a bite or wound that may become infected
Despite common misconceptions, antibiotics are not effective against viral infections, such as the common cold, flu, Coronavirus (COVID-19), most coughs and sore throats. Some people who become infected with COVID-19 may, however, develop complications caused by a bacterial infection. In this case, antibiotics may be prescribed by a health care provider.
Mechanism of action
Antibiotics can prevent or kill bacteria in a number of ways, depending on the structure and mode of action. Antibiotics work by:
- Inhibiting cell wall synthesis – antimicrobial drugs (antibiotics) work by targeting and interfering with the bacterial cell wall synthesis. The cell wall is a thick rigid layer and is a vital structure to maintain the survival of bacteria
- Inhibiting cell membrane function – cell membranes or plasma membranes separate the interior of the cell and are responsible for the movement of substances passing in and out of the cell. Disruption or injuring the cell membrane development can lead to cell leakages and eventually destruction of the bacteria
- Inhibiting protein synthesis – cell growth is prevented or slowed by disruption of the process that leads to the production of new proteins. Without proteins, enzymes and cell structures cannot be created which interferes with and causes death to the cell
- Inhibiting nucleic acid synthesis – DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are critical for cell production. Some antibiotics work by binding to DNA or RNA, which can prevent division or replication and ultimately lead to cell death
Antibiotic resistance
Antibiotic resistance is a growing concern in all parts of the world. Resistance occurs when bacteria change in response to antibiotics, leading to new strains of bacteria. This can result in antibiotic treatment being ineffective and more persistent infections which become difficult to treat and increase the risk of spreading the infection to others. Bacteria which has developed resistance to antibiotics are often referred to as “superbugs” and include infections such as MRSA (Methicillin-Resistant Staphylococcus Aureus).
Antimicrobial resistance (AMR) occurs naturally and can affect anyone, at any age. It can lead to prolonged stays in hospital and increased mortality. New resistance strains are emerging and threaten the once effective and prevention of common infections, making them challenging to treat.
Increased antibiotic resistance has been caused by:
- over use of, continuous or misuse of an antibiotic i.e. taking antibiotics for an infection that will clear on its own
- poor infection prevention and control
- patients who do not complete the entire course of antibiotics
- the widespread use of antibiotics in hospitals has been associated with increases in bacterial strains that no longer respond to treatment with common antibiotics
- over prescribing by health workers, in countries without standard prescribing guidelines
Battle against resistance
With few new antibiotics in development, the prevalence of AMR is increasing. Combating antibiotic resistance is a major priority for the World Health Organisation with a global action plan in place.
It is essential for doctors to appropriately prescribe antibiotics to ensure resistance is kept to a minimum. The UK five Year national action plan “Tackling Antimicrobial Resistance 2019 – 2024) is aimed to effectively contain and control resistance. The three main aims to tackle AMR are:
- reduce the need and unintentional exposure to antimicrobials
- optimising the use of antimicrobials
- investment in innovation, access and supply
For further information, visit: https://www.gov.uk/government/publications/uk-5-year-action-plan-for-antimicrobial-resistance-2019-to-2024
