Antibiotics

• What are antibiotics

  • Many diseases are caused by bacteria (e.g. salmonella food poisoning and gonorrhoea), and can be unpleasant or even fatal 
  • Antibiotics (e.g. penicillin) are medicines that kill bacteria inside the body without harming body cells 
  • Antibiotics cannot be used to destroy viruses

  
• When were antibiotics first discovered

  • In 1928, scientists discovered the first antibiotic, penicillin 
  • It was discovered by Dr Alexander Flemming 
  • The use of antibiotics mean that most bacterial diseases are treatable , and so has greatly reduced the number of deaths from infection 
  • Doctors will prescribe certain antibiotics for certain diseases

  
• Resistant bacterial strains

  • Bacterial strains resistant to antibiotics are increasing  
  • Years ago, doctors discovered that certain antibiotics were no longer effective against certain bacteria 
  • The bacteria had evolved so that they were no longer killed by the antibiotic

  
• How do bacteria become resistant to antibiotics?

  • In any population of an organism, there will be genetic variation due to mutations 
  • It is possible that a mutation could make a bacterium resistant to antibiotics 
  • If an antibiotic were to be used, all of the bacteria would be killed except for the antibiotic resistant bacterium 
  • The antibiotic resistant strain survives and reproduces without any competition from other bacteria 
  • Over time, the population of the resistant strain rises , and the strain will spread as people are not immune to it

  
• What are painkillers

  • Doctors will not describe antibiotics for conditions that might be caused by a virus (e.g. sore throat) 
  • Doctors will prescribe medicines / drugs such as painkillers 
  • Painkillers treat the symptoms of disease by relieving pain 
  • Medicines such as painkiller do not kill pathogens (they do not treat the disease itself)

  
• Why can antibiotics not kill viruses

  • Viruses live and reproduce inside human cells 
  • Because of this, it is difficult to develop drugs that kill viruses without damaging the body cells

  
• How can we reduce the rate at which resistant strains of bacteria develop

  • Doctors should not prescribe antibiotics for non-serious infections, and should not prescribe antibiotics unless they are needed 
  • They should not prescribe antibiotics for viral infections too, as antibiotics have no effect on viruses 
  • Patients should complete their course of antibiotics so that all bacteria are killed , and none survive to form resistant strains 
  • The use of antibiotics in farming should be restricted
• The problem with developing new antibiotics

  • Researchers are currently developing new antibiotics 
  • However, this takes a long time and is extremely expensive 
  • As new antibiotic resistant bacteria emerge all the time, its unlikely that we will be able to keep up