Download Antibiotic Resistance

+
Antibiotic
Resistance
Discovering Antibiotics

Alexander Fleming- 1928

Left his culture of bacteria
exposed overnight. Found
that mold growing on the
plate seemed to kill the
bacteria.

Called it penicillin.

(All antibiotics end with –in)
How do antibiotics work?
 Kills
bacteria by targeting
their life processes.
 Example: Breaks down cell
wall
 Able
to target bacteria onlynot viruses, cells, or
cancerous cells.
 Different
antibiotics target
different parts of the bacteria.
 Example: Some antibiotics
can stop a bacteria from
breaking down food
leaving it to die slowly.
Killing the bacteria
Breaks down
the cell wall
Breaks down
the DNA
+
Evolution and Bacteria
•Slowly bacteria arose that were
resistant to penicillin.
•They were resistant because
their DNA was different and
allowed them to survive in the
presence of penicillin.
•As these resistant bacteria
survived and reproduced there
were many bacterial diseases that
weren’t cured by penicillin
anymore!
+
Antibiotic Resistance
Bacteria could also transfer
their resistance to other
bacteria through:
1. Plasmid Transfer- The
bacteria’s circular DNA
replicated and transferred to
other bacteria.
2. Viral Delivery- A bacteria that
was infected by a virus could
pass on their DNA through
the virus.
3. Free DNA- A Bacteria dies
but its DNA is free to join
another bacteria.
Example: Staph aureus
 Staph
InfectionsOccur most
frequently in
hospitals.
 Bacteria
are resistant
to anti-microbial soap
and many types of
antibiotics.
+
Analogy

If bacteria is an army…

Once swords were invented…they invented armor

Once guns were invented…they invented bullet proof vests

Once biological warfare was invented…they invented gas masks.

They are always trying to make it harder to kill them. (Example:
Taliban hide and don’t wear uniforms-how can we find them?)
+
What can I do?

Don’t use anti-microbial gels like Germ-X too often. It adds
to the resistance of bacteria.

When you take an antibiotic you have to finish the whole
bottle. By not finishing the bottle you are leaving the
strongest most resistant bacteria to survive.

Don’t take antibiotics unless you have to.
+
Review
1.
Who discovered penicillin?_______________
2.
What does an anti-biotic target in the bacteria?
3.
What are the three ways a bacteria can transfer resistance
to another bacteria?
4.
What can you do to stop bacteria from becoming too
resistant?