The antibiotic dilemma

• what is selective toxicity?

  • the ability to interfere with the metabolism of a pathogen without affecting the cells of the host
• what is antibiotic resistance?

  • when bacteria undergoes mutation to become resistant to an antibiotic and then survive to increase in numbers
• how can antibiotic be selectively toxic?

  • unique receptor
  • DNA not coiled as much - different topoisomerase
  • target 70s ribosome, unique to prokaryotic
• how does antibiotic resistance develop?

  • chance mutation in bacteria producing a gene for resistance
  • increase population of resistant
  • strong natural selection for bacteria with resistant gene
  • population with mainly resistant bacteria
  • continued selection/pressure means all bacteria in population will be resistant
• what factors increase likelihood of antibiotic resistance developing?

  • over exposure to antibiotics - taking over provided dose
  • bad hygiene in hospitals/care homes and in general which would increase spread of infection
  • routine expose of antibiotics to animals - accelerates natural selection of antibiotic-resistant strains of both human and animal pathogens
• what does MRSA stand for?

  methicillin-resistant staphylococcus aureus
• how are scientists trying to develop new antibiotics?

  • using computer modelling
  • look at sources of antibiotics in wide variety of places e.g. deep abysses of the oceans
• what are main problems with trying to develop new antibiotics?

  • very expensive
  • can be 10+ years from initial development to potential new product
  • bacterial resistance is always occuring