1. ANTIBIOTIC RESISTANCE

2. Fast breeders Bacteria reproduce very quickly
Eschericia coli can complete a life cycle in 30 minutes
E. Coli

3. Sex in bacteria Bacteria do exchange genes forming new combinations
Bacteria exchange genes is by conjugation
This involves the transfer of genetic material via a cytoplasmic bridge between the two organisms
This can be done between unrelated species of bacteria
Recent studies on bacteria in the wild show that it definitely occurs in the soil, in freshwater and oceans and inside living organisms

4. The magic bullet Antibiotics revolutionised medicine
The first antibiotic, penicillin, was discovered by Alexander Fleming in 1929
It was later isolated by Florey and Chain
It was not extensively used until the 2nd World War when it was used to treat war wounds
After 2nd World War many more antibiotics were developed
Today about 150 types are used
Most are inhibitors of the protein synthesis, blocking the 70S ribosome, which is characteristic of prokaryotes
© 2008 Paul Billiet ODWS

5. Resistance
It took less than 20 years for, bacteria to show signs of resistance
Staphylococcus aureus, which causes blood poisoning and pneumonia, started to show resistance in the 1950s
Today there are different strains of S. aureus resistant to every form of antibiotic in use

6. Multiple resistance
It seems that some resistance was already naturally present in bacterial populations
The presence of antibiotics in their environment in higher concentrations increased the pressure by natural selection
Resistant bacteria that survived, rapidly multiplied
They passed their resistant genes on to other bacteria (both disease causing pathogens and non-pathogens)

7. Transposons & Integrons
Resistance genes are often associated with transposons, genes that easily move from one bacterium to another
Many bacteria also possess integrons, pieces of DNA that accumulate new genes
Gradually a strain of a bacterium can build up a whole range of resistance genes
This is multiple resistance
These may then be passed on in a group to other strains or other species

8. Antibiotics promote resistance
If a patient taking a course of antibiotic treatment does not complete it
Or forgets to take the doses regularly,
Then resistant strains get a chance to build up
The antibiotics also kill innocent bystanders bacteria which are non-pathogens
This reduces the competition for the resistant pathogens
The use of antibiotics also promotes antibiotic resistance in non-pathogens too
These non-pathogens may later pass their resistance genes on to pathogens

9. Resistance gets around
When antibiotics are used on a person, the numbers of antibiotic resistant bacteria increase in other members of the family
In places where antibiotics are used extensively e.g. hospitals and farms antibiotic resistant strains increase in numbers

10. Antibiotic use and abuse
Viral infections are not stopped by antibiotics