antibiotics

• antibiotics 


  -selective toxicity= antibiotics interfere with the metabolism of the bacteria without affecting the metabolism of the human cells.

  • against bacteria
  • eg: streptomycin, amoxicillin, ampicillin
• ways antibiotics damage bacteria


  -polymixines make holes in cell membranes, altering it's permeability.

  -penicillin weakens the cell wall so bacterium is more easily damaged by immune reaction

  -sulfonamides interfere with metabolic reactions

  -streptomycins inhibit protein synthesis
• antibiotic resistance 


  -if a random mutation during reproduction produces a bacterium that isn't affected by the antibiotic, it's best fitted to survive and reproduce, passing antibiotic resistance mutations to daughter cells.

  -bacteria reproduce rapidly, so doesn't take long for a big population of antibiotic resistant bacteria to grow.
• reducing antibiotic resistance 


  -minimising the use of antibiotics

  • ensuring every course of antibiotics is completed to reduce risk of resistant individuals surviving and developing into resistant strains.
  • good hygiene in hospitals
• antibiotic resistant bacteria 


  MRSA= bacterium carried by 30% of population on their skin or in their nose, in body it can cause boils, abscesses and fatal septicaemia.- was treated effectively with methicillin but mutation caused methicillin resistant strains.

  C.difficile= bacterium in guts of 5% of population, produces toxins that damage lining of intestines, when commonly used antibiotics kill off much of the 'helpful' gut bacteria it survives, reproduces and takes hold rapidly.