Antimicrobial Medications

Question 1

Which 2 groups of microbes are sources of most clinically useful antibiotics?

Answer 1

• bacteria

- molds/yeasts

Question 2

What is the strict definition of an antibiotic? (What is a true antibiotic)

Answer 2

• small molecule (smaller than a protein)
• made by a microbe
• effective at low concentrations
• kills or inhibits growth of another microbe

Question 3

What is a semi-synthetic antimicrobial?

Answer 3

-naturally occurring antibiotics that are modified by humans

Question 4

Why are semi-synthetic antibiotics created?

Answer 4

-they can act against bacteria that are resistant to the original compound, have a greater spectrum of activity, or cause fewer side effects

Question 5

What is a synthetic antimicrobial?

Answer 5

-purely human-made molecules

Question 6

What microbes are targeted by antimicrobial medications?

What are more specific terms for these antibiotics?

Answer 6

• bacteria (antibacterial)
• fungi (antifungal)
• protozoans (antiprotozoans)
• helminths (antihelminthic)

Question 7

Which one group of antimicrobial medications are not called antibiotics?

Answer 7

-Antiviral medications (all synthetic)

Question 8

What is selective toxicity?

Answer 8

-ability to kill or inhibit the growth of microbes without harming or damaging human (host) cells.

Question 9

Why is it difficult to find selective poison the more evolutionary related a microbe is to humans?

Answer 9

-enzymes and cellular structures in the microbe are similar to those in human cells

Question 10

What are the 8 groups of microbes under the antimicrobial spectrum?

Answer 10

Prokaryotes:
1) Myobacteria

2) Gram - bacteria
3) Gram + bacteria
4) Chlamydias

Eukaryotes
5)Fungi

6) protozoa
7) helminths
8) Viruses

Question 11

What does it mean if an antimicrobial medication is broad spectrum or narrow spectrum?

Answer 11

• Narrow: affects a single group

- broad: affects at least 2 groups

Question 12

What are the. 6 most common cellular targets for antibacterial medications?

Answer 12

1) Cell wall (peptidoglycan)
2) Ribosome (translation)
3) RNA polymerase (transcription)
4) DNA Replication (DNA gyrase)
5) Bacterial membranes
6) metabolic pathway (actions of enzyme inhibitors)

Question 13

How do antibacterial medications affect cells walls?

Answer 13

• penicillins and cephalosporins inhibit transpeptidase enzyme
  
  • weaken cell wall

Question 14

How do antibacterial mediations affect their target ribosomes?

Examples?

Answer 14

• prevent peptide bond formation (blocks translation)
• aminoglycosides decrease fidelity of ribosome
• Ex. Tetracycline

Question 15

How do antibacterial medications affect their target RNA polymerase?

Answer 15

-stops transcription
if there is no mRNA, ribosomes have no instructions

-rifampin inhibits RNA polymerase

Question 16

How do antibacterial medications affect their target of DNA replication?

Answer 16

-fluoroquinolones inhibit DNA gyrase, an enzymes need for DNA to unwind during DNA replication

Question 17

How do antibacterial medications affect bacterial membranes?

Answer 17

• causes damage to the membrane resulting in the lass of concentration gradients and/or lysis
• ex. Polymyxin B disrupts gram negative outer membrane

Question 18

How antibacterial medications affect metabolic pathways?

Answer 18

• prevents folate synthesis; an essential chemical reaction that builds ATG bases and methionine amino acids
• ex. Sulfa, trimethphan

Question 19

Compare and contrast tetracycline and aminoglycosides

Answer 19

• Tetracycline stops the translation process (bacteriostatic)
• aminoglycosides decrease the fidelity of the ribosome (bacteriocidal)

Question 20

Define bacteriostatic

Answer 20

-capable of inhibiting the growth or reproduction of bacteria

Question 21

Define bacteriocidal

Answer 21

-capable of killing the bacteria

Question 22

List 3 emerging drug resistant bacterial infections

Answer 22

1) MRSA
2) Tuberculosis
3) Gonorrhea bacteria

Question 23

Compare and contrast inherent resistance and specific resistance

Answer 23

• Inherent resistance
  
  • the antibiotic never works against a particular group of microbes (outside the spectrum)
• specific resistance
  
  • certain species/strain develops resistance

Question 24

Define susceptible in context of antimicrobial drugs

Answer 24

-microbial infection is likely to be cured by the antimicrobial medication

Question 25

What are four ways bacteria can attain specific resistance to antibiotics?

Answer 25

1) block entry of antibiotic
2) pump out antibiotic
3) degrade antibiotic
4) alter the target

Question 26

Why are antibiotics given to livestock even when those animals are not suffering form infection?

Answer 26

• will eliminate individuals with certain traits

- the reproduction of survivors will increase frequency of traits that enhanced survival and reproductive success

Question 27

Targets for antifungal medicines (3)

Answer 27

1) plasma membrane: ergosterol in plasma membrane instead of cholesterol
2) metabolic pathway: lipid synthesis enzymes
3) DNA/RNA synthesis

Question 28

Targets for antiprotozoal medicines (2)

Answer 28

1) inhibit DNA synthesis

2) interfere with anaerobic metabolism

Question 29

Targets for antihelminthic medicines (4)

Answer 29

1) block ion channels (paralysis)
2) inhibit ATP production
3) prevent nutrient absorption
4) disrupt membranes

(Severe side effects)