Antibiotics

Question 1

What did early treatment for infectious disease such as syphilis involve?

Answer 1

Use of highly toxic medicines more harmful than the actual disease

Question 2

What did Paul Ehrlich note?

Answer 2

Some dyes (such as methylene blue) stained microbes better than host cells

Question 3

What did Ehrlich come up with?

Answer 3

The idea of a chemical ‘magic bullet’ to kill microbial cells but not the host cells

Question 4

What happened in 1909?

Answer 4

The first selective antibiotic Salvarsan or compound 606

Question 5

What happened in 1982?

Answer 5

Alexander Fleming observed that colonies of the bacterium staphylococcus bacteria could be destroyed by the cold (fungi) penicillium notatum.

Question 6

What could be seen on the culture of staphylococcus bacteria?

Answer 6

A zone surrounding the fungi where bacterial growth was inhibited

Question 7

What is the zone of inhibition used for?

Answer 7

To measure antibiotic susceptibility in the Kirby-bauer test

Question 8

How does penicillin work?

Answer 8

Interfering with the normal formation of the bacterial cell wall by inhibiting the formation of the peptidoglycan cross links

Question 9

How does the penicillin inhibit formation of peptidoglycan cross links?

Answer 9

Blocks the enzyme which stitches the cell wall together

Question 10

What are the bacterial cell components targeted by different classes of antibiotics?

Answer 10

1. Inhibition of cell wall synthesis
2. Inhibition of protein synthesis
3. Disruption of cytoplasmic membrane
4. Inhibition of general metabolic pathways
5. Inhibition of DNA or RNA synthesis
   Special Case: Inhibition of pathogen attachment or entry into host cell

Question 11

What are mutations?

Answer 11

The most important cause of genetic diversity in microbial populations

Question 12

What happens first in antibiotic resistance?

Answer 12

A proportion of the bacterial population gains resistance to antibiotic X by mutation

Question 13

What happens after a proportion of the bacterial population gains resistance to antibiotic X by mutation?

Answer 13

Some bacteria with the resistance survive

Question 14

What happens after some bacteria with the resistance survive?

Answer 14

Bacteria with resistance multiply passing on the resistance trait

Question 15

What happens after bacteria with resistance multiply passing on the resistance trait?

Answer 15

Resistant bacterial populations survive subsequent encounters with Antibiotic X

Question 16

What is beta lactamase?

Answer 16

An enzyme produced by bacteria and used to destroy penicillin

Question 17

How does beta lactamase destroy penicillin?

Answer 17

Breaking a bond in the beta lactic ring to disable the penicillin molecule

Question 18

What are the types of gene transfer in antibiotic resistance?

Answer 18

Vertical and horizontal gene transfer

Question 19

What is vertical gene transfer?

Answer 19

From parent to offspring

Question 20

What is horizontal gene transfer?

Answer 20

From parent to parent

Question 21

How can we reduce development of antibiotic resistance?

Answer 21

Decrease antibiotic utilisation, improve diagnostics, identify new targets and combination therapies

Question 22

What is meant by decrease antibiotic utilization?

Answer 22

Reduce infections and outbreaks through improved hygiene and infrastructure, restrict use in agriculture

Question 23

What is meant by improve diagnostics?

Answer 23

New methods to identify resistant bacteria can make treatment more effective and reduce outbreaks

Question 24

What is meant by identify new targets?

Answer 24

Some cellular pathways are harder for bacteria to bypass or modify, making them ideal targets for new antibodies

Question 25

What is meant by combination therapies?

Answer 25

Traditional antibiotics can be combined with molecules that block resistant mechanisms