Chapter 20: Antimicrobial Drugs (EXAM 3) Flashcards Preview

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Flashcards in Chapter 20: Antimicrobial Drugs (EXAM 3) Deck (23):
1

The use of drugs to treat a disease

Chemotherapy

2

Interfere with the growth of microbes within a host

Antimicrobial Drugs

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

​Antibiotic

4

Killing harmful microbes without damaging the host

Selective Toxicity

5

​Bactericidal

kill bacteria directly

6

Bacteriostatic

Prevent bacteria from growing

7

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

Broad-spectrum antibiotic

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8

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

​Narrow spectrum of microbial activity

9

in 1928: _____ discovered penicillin, produced by Penicillium

Fleming

10

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

Howard Florey

Ernst Chain

11

Innate Immunity

Phagocytic immune cells that have "eaten" bacterial invaders

12

Top 3 killers before Antibiotics (Infectious)

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

13

Top 3 killers after Antibiotics (chronic)

  1. Heart Disease
  2. Cancer
  3. ​Diabetes

14

5 modes of action of antibiotics

  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

 

15

Peptidoglycan (cell wall) inhibitors

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

16

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

Enzyme beta-lactamase

17

Breaks down and inactivates Chloramphenicol

Chloramphenicol acetyltransferase (CAT)

18

Neosporin contains

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

 

19

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

Kirby-Baur Disk-Diffusion Method

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20

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

Minimal inhibitory concentration (MIC)

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21

_______ and ______ ______ arise to antibiotic resistant strains

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

22

5 Cellular Mechanisms used to resist antibiotics

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  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

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23

Misuse of antibiotics selects for resistance mutants

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