Antibiotics and Vaccines

Question 1

What are cidal agents?

Answer 1

Antibiotics that kill organisms are called cidal agents

These agents are termed bacteriocidal, fungicidal
and viricidal agents, killing bacteria, fungi, and
viruses, respectively

Question 2

What are static agents?

Answer 2

Antibiotics that do not kill but only inhibit growth are
called static agents,

These include bacteriostatic, fungistatic and
viristatic agents

Question 3

What does the choice of an antibiotic depend on?

4

Answer 3

on site of infection and the ability of antibiotics to
penetrate that site

Immune response of host

Nature of pathogen

Results of antibiotic susceptibility tests from the
microbiology lab

Question 4

What does the duration of antibiotic treatment depend on?

Answer 4

The site and the pathogen

Question 5

What are broad spectrum antibiotics?

Answer 5

Antibiotics that act on both Gram-positive and Gram-
negative bacteria are called broad-spectrum agents-
useful if pathogen not yet identified, but have
disruptive effect on the microbiome

Question 6

What are narrow spectrum antibiotics?

Answer 6

An antibiotic acting on a single group of organisms-
narrow spectrum agent- preferable when pathogen
has been identified- less effect on microbiome

Question 7

What are the five main antibiotic targets in bacteria?

Answer 7

Cell wall

Protein synthesis

Nucleic acid synthesis

Cytoplasmic membrane

Essential- metabolic pathway- folic acid synthesis

Question 8

How do antibiotics attack the cell wall?

3

Answer 8

Agents inhibit the synthesis of the cell wall

Inhibit the cross-linking of the peptidogylcan- results
in a weak cell wall and osmotic lysis of the bacterium

E.g. of cell wall agents are the β-lactam antibiotics
which includes penicillin, ampicillin and methicillin

Question 9

What type of antibiotics are penicillin and methicilin?

Answer 9

β-lactam antibiotics

Question 10

What are β-lactam antibiotics?

Answer 10

Broad spectrum antibiotics that attach the synthesis of the cell wall

Question 11

How do antibiotics target protein synthesis?

Answer 11

Agents that bind irreversibly to bacterial ribosome

and inhibit protein synthesis

Question 12

Give an example of a type of antibiotic that affects protein synthesis of bacteria.

Answer 12

Aminoglycosides

Question 13

What are aminoglycosides?

3

Answer 13

Narrow spectrum antibiotics used for gram negative bacilli

They target protein synthesis in bacteria

Prolonged usage causes hearing and kidney damage

Question 14

How do antibiotics target nucleic acid synthesis?

2

Answer 14

Inhibitors of DNA replication

Prevent supercoiling of bacterial chromosome

Question 15

Give an example of an antibiotic that targets nucleic acid synthesis.

Answer 15

Fluoroquinolones

Question 16

What are fluoroquinolones?

2

Answer 16

Antibiotics that target nucleic acid synthesis

Broad spectrum - gram + and - infection

Question 17

How do antibiotics target cytoplasmic membrane?

Answer 17

Disorganise structure of the cytoplasmic membrane

Question 18

Give an example of an antibiotic that targets the cytoplasmic membrane.

Answer 18

Amphotericin B (fungal infections)

Question 19

How do antibiotics target folic acid synthesis?

Answer 19

Inhibit synthesis of folic acid

Question 20

Give an example of an agent that targets folic acid synthesis.
(2)

Answer 20

• E.g. sulphonamide and trimethoprim-
act in synergy
• Used in combination in the treatment of
urinary tract infection

Question 21

How does one know the antimicrobial susceptibility of an antibiotic?
(2)

Answer 21

Disc diffusion

Measure the diameter of the zone of inhibition for each antibiotic-
the bigger the zone the more susceptible the isolate

Question 22

What are vaccines?

Answer 22

A vaccine is a preparation which is used to improve

immunity to a particular infection- prevent infection