Transcript Antibiotic Resistance

Antibiotic Resistance
The Challenge in a Changing World
The Scene: Lilly is sick. Poor little girl seems to have some sort of upper
respiratory illness. She is taken into the doctor who wants to be extra sure
this cute little girl gets better. Just to make sure he hasn’t misdiagnosed
her he gives her an antibiotic, even though he is pretty sure it is a virus and
just needs to run its course.
Here is the issue . . . She takes an
antibiotic . . . Methicillin for example. It
kills off 99.99% of the bacteria . . . But
what about that other 0.01%?
It still survives and begins to reproduce like
before except this time with no competition.
As it undergoes binary fission it passes on
its new resistant gene . . .
And now what happens if she really needs
antibiotics? We must use an even stronger
antibiotic. And who is to say that will work
completely? It is a never ending game that
we have created. Are we prepared for it?
Staphylococcus aureus

Frequently living on skin or in your nose

~20-30% of people are Staph carriers
Causes more than 500,000 hospitalized
“Staph infections” in U.S. each year
 Usually treated with Methicillin

MRSA – Methicillin-resistant S. aureus
It has evolved, and continues to do so
 Requires strong antibiotics like
vancomycin = IV only!
 Almost always spread through direct
physical contact


often in hospitals
How do bacteria become resistant?
How do antibiotics work?
• Stop or interfere the cellular processes that bacteria depend on to
survive:
1. Crippling the production of the bacterial cell wall.
2. Interfering with protein synthesis
3. Blocking the synthesis (production or making) of DNA and RNA.
Bacteria come up with ways to counter or fight these actions of the
antibiotics:
1. Changing the permeability of its cell membrane and therefore the
antibiotic cannot be taken up by the cell at all.
2. Changing molecules inside themselves and in doing so ‘confusing’ the
antibiotic so the antibiotic misses the ‘target’.
3. Destroying the antibiotic. Some bacteria produce enzymes that chew
up penicillin.
Non-drug resistant bacteria can get or acquire
resistance by getting a copy of a gene that fights
antibiotics from another drug resistant bacteria!
The result….
http://www.fda.gov/AnimalVeterinary/Saf
etyHealth/AntimicrobialResistance/ucm1
34359.htm
What led to antibiotic resistance?
Overuse of antibiotics…
SUPERBUG - VRSA

VRSA – Vancomycin-resistant S. aureus
What is next? Can we keep up?
The other factor here is, as a society, becoming aware and not overprescribing
antibiotics. Also, not prescribing too many combination antibiotics. Good Luck!!!