Antimicrobial INTRO

Question 1

AM (Antimicrobials) agents can be classified based on 4 things:

Answer 1

1) site of action
2) spectrum of activity (broad or narrow)
3) effect on bacteria (static or cidal)
4) killing kinetics (conc. or time dependent, etc)

Question 2

AM targeting Bacterial cell wall synthesis

Answer 2

• Penicillins
• cephalosporins
• carbapenem + monobactam
• Bacitracin
• Vancomycin
• Cycloserine

Question 3

AM acting on Bacterial cell membrane

Answer 3

Polymyxin B

Colistin

Question 4

AM interfering with Bacterial protein synthesis (mainly static action)

Answer 4

Tetra
Amino
30S

Chloramphenical
Macrolides
Lincosamides
50S

Question 5

AM interfering with Bacterial nucleic acid synthesis

Answer 5

Fluoroquinolones
Metronidazole
(DNA synthesis)

Rifampin (RNA synthesis)

Question 6

AM interfering with Bacterial folic acid synthesis

Answer 6

Sulfonamides

Diaminopyrimidines

Question 7

Broad Spectrum

Answer 7

Sulfonamides
Tetracyclines
chloramphenicol 
Macrolides+Lincomycin
Fluoroquinolones
Rifampin

Question 8

Narrow Spectrum (mainly Cidal action)

Answer 8

B-Lactams, particularly natural penicillin
Aminoglycosides
Polymyxin B
Colistin

Question 9

Bactericidal

Answer 9

B-Lactams-cell wall synthesis
Poly B-cell membrane
Colistin-cell membrane
Aminoglycosides-30S
Fluoroquinolones-dna syn
Metronidazole-dna syn

Question 10

Bacteriostatic

Answer 10

Sulfonamides-folic acid syn
Tetracyclines-30S
Chloramphenicol-50S
Macrolides-50S
Lincomycin-50S

Question 11

Killing Kinetics: Type 1 Concentration Dependent

Answer 11

peak drug concentration at the site of infection exceeds the MIC or is around the MIC

Question 12

Killing Kinetics: Type 2 Time Dependent

Answer 12

drug concentration is kept at or above the MIC

Question 13

Killing Kinetics: Type 3 Time dependent and Post ABX effect

Answer 13

drug concentration in plasma provides abx effect after abx exposure plus the whole bit about MIC

Question 14

Benefits of combination therapy

Answer 14

• You can treat mixed bacterial infections
• synergy of effects
• decreased drug resistance
• decreased toxicity
• prevent inactivation by bacterial enzymes

Question 15

So, what are 3 things that combination therapy yields?

Answer 15

synergy-CIDAL
additive-STATIC
antagonistic-CIDAL AND STATIC

Question 16

Resistance can be ___ or ___

Answer 16

natural or acquired

Question 17

Acquired resistance is due to:

Answer 17

chromosomal mutations changing DNA

plasmidsresistanceRGene

Question 18

Resistance happens 3 ways:

Answer 18

Conjugation (sex pilus)

Transfer of RGene

Question 19

Transformation

Answer 19

happens through the environment

Question 20

Transduction (bacteriophage)

Answer 20

with virus involved, no need for contact between resistant and susceptible bacteria

Question 21

1: Way that bacteria can inactivate antibiotivs via acquired genes

Answer 21

With the use of enzymes to destroy the AM or prevent it from binding to target sites

Question 22

2: Mutations can allow bacteria to

Answer 22

structurally modify the AM target site thereby decreasing drug efficacy

Question 23

3: Bacteria can decrease drug accumulation within by

Answer 23

increasing number of porins that don’t allow the drug to enter. Result? decrease drug permeability and increase drug efflux

Question 24

4 Doing what to the metabolic pathway?

Answer 24

Creating an alternate one…ex Sulfonamide and PABA