1. Antibiotics
Biology Presentation

2. Antibiotics About Antibiotics About Antibiotic Resistance
Something we should know when we take antibiotics

3. 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)

4. 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 ( ), two other British scientists, Florey and Chain successfully managed to produce antibiotics in industrial scale for widespread use.

5. 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)

6. 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

7. 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.

8. 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

9. 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.

10. 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

11. About Antibiotics Resistance: Why do bacteria become resistant to antibiotics?
Natural phenomenon
4. Eventually there are more antibiotic-resistant bacteria than non-resistant.
2. The bacteria with resistance survive after the antibiotics are gone.
and reproduce, inherit the resistant genes to their offspring.
1. Antibiotics attack and kill off bacteria without resistance.

12. 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)

13. 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

14. 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

15. 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.

16. About Antibiotics Resistance: How does antibiotic resistance spread?
Environmentally
Via airplane, water and wind, coughing, or contact of unwashed hands.

17. 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

18. 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

19. 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

20. Please Take Care (o^_^o)
Presented by
6B Law Wei Bong

21. Reference URL AUPA: Alliance for the Prudent Use of Antibiotics
Medem Inc.
Medline plus
The Microbial World
Stalking the Mysterious Microbe
mutations.asp