Chapter 20: Antimicrobial Drugs (EXAM 3)

Question 1

The use of drugs to treat a disease

Answer 1

Chemotherapy

Question 2

Interfere with the growth of microbes within a host

Answer 2

Antimicrobial Drugs

Question 3

A substance (small, organic) produced by a microbe that, in small amounts, inhibits another microbe

A substance produced by a microorganism that slows growth or kills bacteria

Answer 3

​Antibiotic

Question 4

Killing harmful microbes without damaging the host

Answer 4

Selective Toxicity

Question 5

​Bactericidal

Answer 5

kill bacteria directly

Question 6

Bacteriostatic

Answer 6

Prevent bacteria from growing

Question 7

An antibiotic that is effective aginst a wide range of both gram-positive and gram-negative bacteria

Answer 7

Broad-spectrum antibiotic

Question 8

Some drugs have a _____ ______ __ _______ ______, or range of different microbial types that they affe

Answer 8

​Narrow spectrum of microbial activity

Question 9

in 1928: _____ discovered penicillin, produced by Penicillium

Answer 9

Fleming

Question 10

in 1940: ____ _____ and ____ _____ performed first clinical trials for penicillin

Answer 10

Howard Florey

Ernst Chain

Question 11

Innate Immunity

Answer 11

Phagocytic immune cells that have “eaten” bacterial invaders

Question 12

Top 3 killers before Antibiotics (Infectious)

Answer 12

1. ​​​​​Pneumonia
2. Tuberculosis
3. ​Diarrhea

Question 13

Top 3 killers after Antibiotics (chronic)

Answer 13

1. Heart Disease
2. Cancer
3. ​Diabetes

Question 14

5 modes of action of antibiotics

Answer 14

1. Inhibition of Cell Wall Synthesis
2. Inhibition of Protein Synthesis
3. Inhibition of Nucleic Acid replication
4. Injury to Plasma Membrane
5. Inhibition of Essential Metabolite synthesis

Question 15

Peptidoglycan (cell wall) inhibitors

Answer 15

• Vancomycin (inhibits gram +, can’t get through outer membrane of gram -)
• Penicillin (B-lactam)
• Bacitracin

Question 16

Selectively hydrolyzes the B- lactam ring of antibiotics such as penicillin and amoxicillin

Answer 16

Enzyme beta-lactamase

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Question 17

Breaks down and inactivates Chloramphenicol

Answer 17

Chloramphenicol acetyltransferase (CAT)

Question 18

Neosporin contains

Answer 18

• Polymyxin B- damages gram - outer membranes causing cell leakage
• Bacitracin- inhibits cell wall synthesis
• Neomycin - inhibits protein synthesis

Question 19

An agar-diffusion test to determine microbial susceptibility to chemotherapeutic agents

Answer 19

Kirby-Baur Disk-Diffusion Method

Question 20

The lowest concentration of a chemotherapeutic agent that will prevent growth of the test microorganisms

Answer 20

Minimal inhibitory concentration (MIC)

Question 21

_______ and ______ ______ arise to antibiotic resistant strains

Answer 21

Mutations and Natural Selection

Mutations that confer resistance arise by spontaneous mutations that are transferred vertically or by horizontal transfer of resistance genes

Antibiotics kill defenseless bacteria leaving behind (selecting) antibiotic resistant bacteria which then multiplies, passing the resistance gene on to their offspring

Question 22

5 Cellular Mechanisms used to resist antibiotics

Answer 22

1. Decreased Cell Permeability (altered surface charges, thickened peptidoglycan, altered membrane proteins involved in transport)
2. Antibiotic Efflux Pumps
3. Antibiotic Degradation
4. Antibiotic Modification
5. Target Alteration

Question 23

Misuse of antibiotics selects for resistance mutants

Answer 23

Misuses include:

• using outdated or weakened antibiotics
• using antibiotics for the common cold and other inappropriate conditions
• using antibiotics in animal feed
• failing to complete the prescribed regimen
• using someone else’s leftover prescription