Antibiotics

-Damage bacteria and eventually kill them

-Each type of antibiotic inteferes with the bacterias life process (making a cell wall)

-Doesn't kill viruses, protozoa or fungi

-Doesn't affect human cells

-Treated battlefield injuries during WW2

-Discovered 'richly fertile' soil caused deadly infections because it was rich in microorganisms

-Searched for compounds to kill bacteria

-Put an experiment in a bath of antiseptic before he went on holiday when mould started to grow

-Realised mould prevented bacteria from growing and killed existing bacteria

-Proved it was harmless to human cells by testing it on open wounds and his own blood

-Bacteria can mutate which could cause them to be antibiotic resistant

-If you have an infection some of the bacteria may be antibiotic resistant. This means only the non resistant strains of bacteria will be killed

-The individual resistant bacteria will survive and reproduce and the population will increase 

-The resistant strain could cause a serious infection that can't be treated by antibiotics

-Should finish the whole course of antibiotics

-Lot of natural variation

-Some Staphylococcus become naturally resistant due to a genetic mutation or genetic variation

-The weaker cells die out when the patient is given antibiotics

-No normal cells die

-Resistant MRSA survive

-Surviving cells multiply

-Only Staphylococcus left are MRSA