Antibiotics

Question 1

Define Antibiotics

Answer 1

These are natural products of fungi and bacteria -soil dwellers
Natural antagonism and selective advantage
Kill or inhibit the growth of other micro-organisms

Most derived from natural products through fermentation then get modified chemically

This tends to increase their pharmacological properties and antimicrobial effects

Question 2

What is a main principle of antibiotics being used as a therapeutic agent ?

Answer 2

Being selectively toxic

Due to differences in structure and metabolic pathways between host and pathogen

Harm micro-organisms not the host

Target in microbe not host

Difficult for viruses (intracellular ),fungi and parasites

The effect it will have on commensal flora

Question 3

What is therapeutic margin ?

Answer 3

The active dose (MIC) versus toxic effect

This is narrow for toxic drugs such as
aminoglycosides,vancomycin
(ototoxic and nephrotoxic)

There are no safe drugs so the therapeutic imperative is balanced with host damage

Question 4

What does MIC stand for ?

Answer 4

Minimum inhibitory concentration

Question 5

What is ototoxic ?

Answer 5

the property of being toxic to the ear

Question 6

What is nephrotoxic ?

Answer 6

This is the toxicity to the kidneys

Question 7

Define microbial antagonism

Answer 7

Maintains flora-complex interactions

Competition between flora

Limits the growth of competitors and pathogens

Question 8

What is antibiotic associated colitis?

Answer 8

This occurs when broad spectrum highly potent antibiotics damage the flora leading to an overgrowth of pathogen /bacteria.

This means that clostridium dificile will over grow

Question 9

What are some factors which may cause immunosuppression ?

Answer 9

SLIDE

Question 10

What are the three categories through which antibiotics are classified ?

Answer 10

Activity
Structure
Target site

Question 11

What are bactericidal antibiotics ?

Answer 11

These kill bacteria
Used when the host defence mechanism are impaired
Required in endocarditis, kidney and infection

Question 12

What are bacteriostatic antibiotics ?

Answer 12

These will inhibit bacteria
These are used when the host defence mechanism are intact
Used in infectious diseases

Question 13

What are the two antibiotic spectrum types ?

Answer 13

Broad specturm antibiotics
Effective against many types
e.g. Cefotaxime

Narrow spectrum antibiotics
Effective against very few types
Penicillin G

Question 14

What are the different structures of antibiotics ?

Answer 14

SLIDE

Dont need to learn

Question 15

What are some targets on bacteria for selective toxicity ?

Answer 15

SLIDE