Antibiotics & Painkillers (AQA GCSE Biology: Combined Science)

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Antibiotics & Painkillers

  • When treating a disease there are two types of medication that an individual can take:
    • Medicines that treat the cause of the disease – antibiotics
    • Medicines which treat the symptoms of the disease – eg. painkillers

  • Antibiotics, such as penicillin, are medicines that help to cure bacterial disease by killing infective bacteria inside the body
  • The use of antibiotics has greatly reduced the deaths from infections in the last century
  • Only certain antibiotics will work on certain diseases, however, so a doctor will prescribe different antibiotics depending on the type of infection (see Culturing Microorganisms)
  • It is important that specific bacteria should be treated by specific antibiotics that are known to work against them
  • Antibiotics work by stopping bacteria cellular processes such as the production of the cell wall – they affect processes usually only in bacteria so are not harmful to animal cells

 

How antibiotics work, IGCSE & GCSE Biology revision notes

Penicillin was the first antibiotic to be discovered and is widely used, although resistance is a problem

  • Antibiotics will not work against viruses, as viruses reproduce inside cells. It is difficult to develop drugs that kill viruses without also damaging the body’s tissues
  • Painkillers and other medicines are used to treat the symptoms of disease but do not kill pathogens (eg. ibuprofen can reduce pain and inflammation)

Antibiotic Resistance

  • The use of antibiotics has increased exponentially since they were first introduced in the 1930s
  • In that time they have saved millions of lives

 Antibiotic effect, downloadable IGCSE & GCSE Biology revision notes

The introduction of antibiotics has had one of the largest impacts on global health, shown by this example in the USA

  • However, since their discovery and widespread use, antibiotics have been overused and antibiotic resistance has developed in many different types of bacterial species
    • Bacteria, like all organisms, have random mutations in their DNA
    • One of these mutations may give them resistance to an antibiotic
    • If an organism is infected with bacteria and some of them have resistance, they are likely to survive treatment with antibiotic
    • The population of the resistant bacteria will increase
    • If the resistant strain is causing a serious infection then another antibiotic will be needed
    • A strain of Staphylococcus aureus has developed resistance to a powerful antibiotic methicillin, this is known as MRSA (Methicillin resistant Staphylococcus aureus)
    • MRSA can infect wounds and is difficult to treat without antibiotics

Antibiotic_resistance, IGCSE & GCSE Biology revision notes

Bacteria evolve rapidly as they reproduce quickly and acquire random mutations – some of which confer resistance

Preventing resistant bacteria

  • To reduce the number of bacteria that are becoming resistant to antibiotics:
    • Doctors need to avoid the overuse of antibiotics, prescribing them only when needed – they may test the bacteria first to make sure that they prescribe the correct antibiotic
    • Antibiotics shouldn't be used in non-serious infections that the immune system will ‘clear up’
    • Antibiotics shouldn't be used for viral infections
    • Patients need to finish the whole course of antibiotics so that all the bacteria are killed and none are left to mutate to resistant strains
    • Antibiotics use should be reduced in industries such as agriculture – controls are now in place to limit their use in farming

Reducing the spread of resistant strains

  • Good hygiene practices such as handwashing and the use of hand sanitisers have reduced the rates of resistant strains of bacteria, such as MRSA, in hospitals
  • The isolation of infected patients to prevent the spread of resistant strains, in particular in surgical wards where MRSA can infect surgical wounds

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Lára

Author: Lára

Expertise: Biology Lead

Lára graduated from Oxford University in Biological Sciences and has now been a science tutor working in the UK for several years. Lára has a particular interest in the area of infectious disease and epidemiology, and enjoys creating original educational materials that develop confidence and facilitate learning.