ANTIBIOTICS
• Have you ever taken antibiotics when you were
sick?
• What illness did you have? How long did you take
them for?
THE BIG PICTURE: “HOW CAN WE KILL
BACTERIA THAT ARE MAKING US ILL?”
• Learning outcomes:
• Explain what antibiotics are used for.
• Analyse how antibiotic resistance can occur.
• To evaluate how we can stop the spread of antibiotic resistance.
ANTIBIOTICS
Antibiotics are medicines used
to treat bacterial infections.
They do not work on viruses!
HOW ANTIBIOTICS
WORK
• Antibiotics work by being either:
– bactericidal (kill bacteria)
– bacteriostatic (inhibit the growth of the
bacteria)
• Example: Penicillin
– Bactericidal antibiotic
– Works by preventing the production of a
substance that form the cell wall.
– The cell will continue to grow without
dividing or developing new cell wall.
– Therefore, the wall gets weaker, and
eventually ruptures
YOUTUBE VIDEO
• https://www.youtube.com/watch?v=X1GT2bKgci8
ANTIBIOTIC RESISTANCE
• Antibiotic resistance is when an antibiotic is
no longer effective
– A bacteria that used to be killed by a
drug isn’t affected by it any more
• Antibiotic resistance is driven by overusing
antibiotics and prescribing them
inappropriately.
A natural population of bacteria has some weak and some strong bacteria.
You start taking an antibiotic…
The weak bacteria die first
You keep taking the antibiotic, more bacteria die
Until eventually only the strong bacteria are left. The are resistant (not affected
by the antibiotics.
You stop taking the antibiotic
The strong, resistant bacteria reproduce
Now there are lots of resistant bacteria which antibiotics cannot kill!
ANTIBIOTIC RESISTANCE
• Another way bacteria can become resistant is through mutation
• A mutation is a random change in the genetic material of the bacteria
• This can cause the genetic material to make the bacteria resistant to harm by the drug.
YOUTUBE VIDEO
• https://www.youtube.com/watch?v=mngVeKX8plk
• Play till 1.40