Transcript Document 7348676

Antibiotics
Biology Presentation
Antibiotics
About Antibiotics
About Antibiotic Resistance
Something we should know
when we take antibiotics
About Antibiotics:
What is antibiotics?
Chemical Compounds
Able to kill or inhibit the growth of bacteria (e.g. human)
without causing significant damage to the host
Naturally produced (e.g. penicillin) by mold or bacterium,
or
Synthetically made (e.g. fluoroquinolones)
About Antibiotics:
Discovery of antibiotics
In 1929, first discovered by British Scientist
Alexander Fleming.
However, he could not purify the compound due to its
instability.
Until the period of World War II (1939-1945), two other
British scientists, Florey and Chain successfully managed
to produce antibiotics in industrial scale for widespread
use.
About Antibiotics:
How do antibiotics work?
Bacteriostatic antibiotics (e.g. Penicillin)
Not actually kill the bacteria
Stop the cells from growing and multiplying
Allows time for the infected host to mount an immune
response  Eliminate the non-growing infectious agent
(i.e. the bacteria)
About Antibiotics:
How do antibiotics work?
Bacteriocidal antibiotics
Actually kill the bacteria
Preferred choice when the patient’s immune
system is weakened or incapable of
destroying the organisms itself
About Antibiotics:
How do antibiotics work?
In both cases, bacteriostatic and bacteriocidal
antibiotics disrupt the bacterial cells by attacking:
the outer cell wall or inner membrane, or
the chemical pathways necessary for the bacteria
to live or reproduce.
NO activities against most of the viruses.
About Antibiotics:
How do antibiotics work?
E.g. Penicillin
Prevents the cross-linking of small peptide chains
in the main cell wall polymer of bacteria.
Pre-existing cells are not affected.
All newly produced cells grow abnormally
Unable to maintain cell wall rigidity
About Antibiotics:
How are antibiotics used?
In medical ways:
 to treat illness caused by bacteria
to prevent bacterial infections in surgery
In the supply of food:
to increase the growth of certain
food animals
used as pesticides to control
bacterial infections in food crops.
About Antibiotics Resistance:
What is antibiotic resistance?
An antibiotic lost its ability to effectively control
or kill bacterial growth.
i.e. bacteria are “resistant” and continue to
multiply in the presence of therapeutic levels of
and antibiotics
About Antibiotics Resistance:
Why do bacteria become resistant to
antibiotics?
Natural phenomenon
2. The bacteria
with resistance
survive after the
antibiotics are
gone.
1. Antibiotics
attack and kill
off bacteria
without
resistance.
3. ....and
reproduce,
inherit the
resistant
genes to
their
offspring.
4. Eventually
there are more
antibioticresistant
bacteria than
non-resistant.
About Antibiotics Resistance:
Why do bacteria become resistant to
antibiotics?
Resulting in the survival of resistant strains of
bacteria. survival for the fittest  “Natural
Selection”
Low-level of natural selection  produced by
bacteria to against each other (w/out human
action)
High-level of natural selection  by overuse of
antibiotics (human action)
About Antibiotics Resistance:
How do bacteria become resistant?
By genetic mutation
Chance: 1 / 1,000,000 – 10,000,000
 produce enzyme to inactivate the
antibiotics
 eliminate cell target that the antibiotic
attacks
About Antibiotics Resistance:
How do bacteria become resistant?
By acquiring resistance from another bacterium
 by conjugation
Bacteria have the ability to “collect” multiple
resistant traits over time  resist to many
different families of antibiotics
About Antibiotics Resistance:
How does antibiotic resistance spread?
“Vertically”  new
generations inherit
antibiotic resistance genes.
“Horizontally”  share or
exchange genes with other
bacteria , even occur between
different species.
About Antibiotics Resistance:
How does antibiotic resistance spread?
Environmentally
Via airplane, water and wind, coughing, or
contact of unwashed hands.
About Antibiotics Resistance:
Can bacteria lose their antibiotic resistance?
YES
Slow process
Stop using antibiotics for a while  the
population of bacteria that responds to antibiotics
increases
Something we should know when we
take antibiotics
Antibiotics may cause side effects
(e.g. nausea, diarrhea and stomach pain)
In some people, an allergic reaction
(characterized by rash and itching; or in severe
cases, difficulty breathing) can occur
Should only be used when prescribed by your
doctor
Something we should know when we
take antibiotics
must be taken for the full amount of time
prescribed by your doctor
should not be saved and reused
Please Take Care
(o^_^o)
Presented by
6B Law Wei Bong
Reference URL
AUPA: Alliance for the Prudent Use of Antibiotics
http://www.healthsci.tufts.edu/apua/apua.html
Medem Inc.
http://www.medem.com/medlb/article_detaillb.cfm?article_ID=ZZZPT8692
8C&sub_cat=277
Medline plus
http://www.nlm.nih.gov/medlineplus/antibiotics.html
The Microbial World
http://helios.bto.ed.ac.uk/bto/microbes/penicill.htm
Stalking the Mysterious Microbe
www.microbe.org/microbes/ mutations.asp