Chpt 12 Chemotherapy

Question 1

Antimicrobial Chemotherapy

Answer 1

Admistering a drug to an infected person that destroys the infective agent without harming the host’s cell

Question 2

Antibiotics

Answer 2

Substance naturally made by metabolic processes that can inhibit or destroy other microorganisms

Question 3

Selectively Toxic

Answer 3

A drug which kills or inhibits growth of microbes without damaging host tissue

Question 4

What 5 mechanisms do antibiotics use to target pathogens

Answer 4

1. Inhibits cell wall synthesis
2. Breakdown Cell membrane structure or function
3. Inhibits structure and function of DNA and RNA
4. Inhibition of Protein Synthesis
5. Blocks metabolic pathways

Question 5

Narrow-Spectrum Drugs

Answer 5

drugs effective on a small range of cell types

Question 6

Broad-spectrum drugs

Answer 6

Effective on the greatest range of cell types

-usually effects common cell components such as ribosomes

Question 7

Which drugs affect Bacterial Cell Wall

Answer 7

1) Penicillins
2) Cephlasporins
3. Bacitracin
- Block peptidases that cross-link the glycan molecules (in peptidoglycan cell walls)

Question 8

Which drugs disrupts cell membrane function

Answer 8

1. Polymyxins - cause leakage of proteins and nitrogen bases

Question 9

Which drugs affects Nucleic Acid Synthesis

Answer 9

1. Chloroquines (an antimalarial drug) - binds and cross links the double helix
2. Quinolones - inhibit DNA unwinding enzymes or helicase

Question 10

Which drugsblocks protein synthesis

Answer 10

1. Aminoglycosides
2. Tetracyclines
3. Chloramphenicol
4. Erythromycin (Macrolides)
5. Oxazolidinones

Question 11

Beta-Lactams are in which antibiotic

Answer 11

-Penicillin and Cephlasporins

Question 12

Which Drugs block Metabolic Pathways

Answer 12

1. Sulfonamides (sulfa drugs)
2. Trimethoprim
   - Inhibit folic acid formation

Question 13

Antimicrobial which acts against Fungi

Answer 13

1. Amphotericin B
2. Azoles (-zole)
3. Flucytosine

Question 14

Antimicrobial which acts against Protozoa

Answer 14

1. Quinines (-quine)

2. metronidazole

Question 15

Antimicrobial which acts against Viruses

Answer 15

1. Amantidine
2. Cyclovirs
3. Azidothymidine

Question 16

Antimicrobial which acts against helminths

Answer 16

1. Mebendazole

2. Thiabendazole

Question 17

Drugs that treat influenza

Answer 17

1. Amantidines
   - Tamiflu
   - Relenza

Question 18

Antiherpes drug

Answer 18

1. Acyclovir (Zovirax)

- -cyclovir

Question 19

1st drug to treat HIV

Answer 19

1. Zidovudine (AZT)
   - First nucleoside analog reverse transcriptase inhibitors
   - Blocks Viral DNA production

Question 20

2 types of HIV drugs

Answer 20

1. Nucleoside analog reverse transcriptase inhibitor
   - Has thymine analog and terminates synthesis
2. Non-nucleoside reverse transcriptase inhibitor
   - Binds to HIV RT binding site, stopping its action

Question 21

Interferon

Answer 21

Has antiviral and Anticancer properties

-not viral specific

Question 22

Interferon function

Answer 22

• virus binds to receptors on host cell
• signal sent to cells nucleus
• interferon synthesized and secreted to extracellular space and bind to adjacent cells
• Other cells begin producing other proteins which inhibit viral multiplication by preventing translation of viral proteins

Question 23

Specific Mechanisms of Drug resistance

Answer 23

1. Microbial enzyme inactivates drug
2. Permeability or uptake of drug into bacterium is reduced or eliminated
3. Special drug transport pump removes drug (much like ATPase)
4. Binding site for drug are reduced
5. Affected metabolic pathway is shutdown or alternate pathway is used (need mutation of original enzyme)

Question 24

Drug inactivation mechanisms

Answer 24

Beta-lactamases

- Destroys beta-lactam ring structure in penicillin and cephalosporine so their activity is lost

Question 25

Decreased Permeability (drug resistant mech.)

Answer 25

Alters receptors on membrane so drug cant bind

Question 26

Activation of drug pump (resistance mech)

Answer 26

Membrane proteins activated and pump drug out of cell

Question 27

Change in binding site (resistance mech)

Answer 27

Binding site on target (such as ribosome) is altered so drug has no effect

Question 28

Use of alternate metabolic pathways (resistance mech)

Answer 28

Drug blocks usual pathway, so the microbe uses alternate pathway to achieve end product

Question 29

Superinfections

Answer 29

When chemotherapy destroys beneficial resident species (natural biota which kept harmful microbes in check) resistant microbes can begin to overgrow an cause disease

Question 30

The Kirby-Bauer Test

Answer 30

Tests antimicrobial susceptibility - Disc with antimicrobial placed in bacterial lawn on agar plate - after incubation zone of inhibition surrounding the disc is measured. - The greater the zone of inhibition the greater the bacterium's sensitivity to drug is

Question 31

Minimum inhibitory Concentration

Answer 31

The smallest concentration of drug that visibly inhibits growth Smallest concentration needed to inhibits growth of microorganisms

Question 32

Nucleoside analog reverse transcriptase inhibitors

Answer 32

-Stop the action of reverse transcriptase in HIV which blocks DNA production

Question 33

Non-nucleoside reverse transcriptase inhibitors

Answer 33

Attach to HIV Reverse Transcriptase binding site thereby stopping its action