Micro1009- Chapter 20 Antimicrobial Drugs

Front 1

First microbiologist to search for what we now know as antibiotics? What was he searching for?

Back 1

Paul Ehrlich

Searched for a "magic bullet", or selective toxicity

Front 2

Selective toxicity

Back 2

A characteristic that causes the death of microbes while leaving host tissue unharmed

Front 3

What term did Paul Ehrlich coin?

Back 3

Chemotherapy

Front 4

Chemotherapy

Back 4

Using chemicals to treat a disease

Front 5

Who invented penicillin?

Back 5

Alexander Fleming

Front 6

How was Penicillin invented?

Back 6

A plate of Staphylococcus aureus was left out and grew mold, specifically the genus Penicillium. It was found that this mold inhibited the growth of the bacteria

Front 7

Antibiotics

Back 7

Substances produced by microorganisms that inhibit the growth of other microorganisms

Front 8

Sulfa Drugs

Back 8

Developed by three Germans during WWII to combat Streptococcal infections

Technically not an antibiotic because it was derived from a chemical, not microbe

Front 9

What is the source of more than half of antibiotics?

Back 9

Streptomyces

Front 10

What are some other sources of antibiotics?

Back 10

- Bacillus subtilis produces Bacitracin

- Molds such as Penicillium and Cephalosporium

Front 11

Spectrum classifications of antimicrobial activity

Back 11

1. Narrow spectrum

2. Broad spectrum

Hint 11

2

Front 12

Narrow spectrum

Back 12

Antibiotics only affect a few organisms

Front 13

Broad spectrum

Back 13

Large range of organisms is affected

Overused

Damage normal flora

Front 14

Example of broad spectrum activity

Back 14

Some drugs that combat both gram + and gram- bacteria

Front 15

What are some limitations in antimicrobial activity against organisms other than bacteria? What is the significance?

Back 15

- protozoans, fungi, and helminths are more closely related to humans

- viruses aren't cellular and only reproduce inside cells using our cellular machinery

- antibiotics tend to be more effective against bacteria

Front 16

What is the purpose of bacteriostatic agents against infection?

Back 16

The inhibited growth allows the immune system to catch up and destroy the organisms

Front 17

How does penicillin act against microbes?

Back 17

Inhibits cell wall synthesis by blocking peptidoglycan synthesis

This leads to cell lysis

Front 18

Drugs that inhibit cell wall synthesis

Back 18

1. Natural penicillins

2. Semisynthetic Penicillins

3. Cephalosporins

4. Polypeptide antibiotics

Hint 18

4

Front 19

Semisynthetic penicillins

Back 19

Amoxicillin

Ampicillin

Carbapenems

Monobactams

Hint 19

4

Front 20

Cephalosporins

Back 20

Resemble Penicillin, but beta-lactam ring is slightly different

Front 21

Polypeptide antibiotics

Back 21

Bacitracin

Vancomycin

Front 22

Bacitracin

Back 22

Topical antibiotic derived from B. subtilis

Front 23

Vancomycin

Back 23

Used to combat MRSA

Front 24

How have certain bacteria built a resistance to penicillins and cephalosporins?

Back 24

They have developed the ability to cut up beta-lactam rings, making these classes ineffective

Front 25

Ways that drugs target microbes

Back 25

1. Inhibition of cell wall synthesis

2. Inhibition of protein synthesis

3. Injury to the plasma membrane

4. Inhibition of nucleic acid synthesis

5. Inhibition of the synthesis of essential metabolites

Hint 25

5

Front 26

Drugs that act as inhibitors of protein synthesis

Back 26

1. Aminoglycosides

2. Tetracyclines

3. Macrolides

Front 27

How do drugs inhibit protein synthesis?

Back 27

Bacterial ribosome differs from what is found in eukaryotic ribosomes, so drugs can be made to target them and prevent protein synthesis

Front 28

Macrolides

Back 28

Erythromycin

Azithromycin

Front 29

Aminoglycosides

Back 29

Streptomycin

Gentamicin

Hint 29

2

Front 30

How do antibiotics injure plasma membranes?

Back 30

By binding to the cell membrane and changing its permeability, leading to lysis

Front 31

How do some antifungal bind to the cell membrane of fungi?

Back 31

They bind to sterols in the phospholipid bilayer

Front 32

What drugs cause injury to the plasma membranes of microbes?

Back 32

1. Polymyxin B

2. Lipopeptides

Hint 32

2

Front 33

What is an example of a Lipopeptide?

Back 33

Daptomycin

Front 34

What is a common use for daptomycin

Back 34

Used against MRSA

Front 35

How do some antibiotics inhibit nucleic acid synthesis?

Back 35

By interfering with DNA replication or transcription by targeting DNA gyrase and RNA polymerase

Front 36

What is the affect of antibiotics targeting DNA gyrase?

Back 36

Bacteria can't uncoil DNQ

Front 37

Antibiotics that inhibit Nucleic acid synthesis

Back 37

- Rifampin

- Quinolones

- Fluoroquinolones

Front 38

Fluoroquinolones

Back 38

Ciprofloxacin

Levofloxacin

Front 39

How do drugs inhibit the synthesis of essential metabolites?

Back 39

Some drugs block the synthesis of folic acid, which is synthesized by bacteria but not humans

Front 40

What are common drugs that inhibit the synthesis of essential metabolites and how do they do it?

Back 40

Sulfa drugs, by mimicking PABA, which is a precursor to folic acid

Front 41

Types of antiviral drugs

Back 41

1. Nucleotide analogs

2. Enzyme inhibitors

3. Interferons

Hint 41

3

Front 42

Nucleotide analogs

Back 42

Drugs that mimic nucleotides, preventing viral replication

Front 43

What is an example of a common Nucleotide analog?

Back 43

Acyclovir

Front 44

Enzyme inhibitors

Back 44

Block viral enzymes

Front 45

What is an example of a common enzyme inhibitor and how does it work?

Back 45

Tamiflu

Blocks neuraminidase in influenza

Front 46

Interferons

Back 46

Proteins that are produced by cells infected with a virus

Cause uninfected cells to produce antiviral proteins

Front 47

How do we test the effectiveness of antibiotics?

Back 47

Disk diffusion method

Front 48

Disk diffusion method

Back 48

Adding discs laden with antibiotics to a spread plate and looking for zones of inhibition

Front 49

How do we determine the necessary strength of an antibiotic?

Back 49

We find the Minimal Inhibitory Concentration (MIC) by using a broth dilution test to find the lowest concentration of an antibiotic that will still prevent bacterial growth

Front 50

Mechanisms of resistance to antimicrobial drugs

Back 50

1. Enzymatic destruction or inactivation of the drug

2. Blocking entry/ prevention of penetration to target site

3. Alteration of the target molecule

4. Rapid efflux of the antibiotic

Front 51

Enzymatic destruction or inactivation of the drug

Back 51

B-Lactamases target the B-lactam ring shared by penicillins and cephalosporins

Front 52

Blocking the entry/ prevention of penetration to the target site

Back 52

Some bacteria alter the structure of porins, which no longer allow entry of the antibiotic

Front 53

Alteration of the target molecule

Back 53

Minor changes in the structure of bacterial proteins can prevent the antibiotic from binding to them

Front 54

Rapid efflux of the antibiotic

Back 54

The bacteria have molecular pumps that spit the antibiotics out of the cell before they can have an effect

Front 55

Effects of combining drugs

Back 55

1. Synergism

2. Antagonism

Hint 55

2

Front 56

Synergism

Back 56

When 2 or more antibiotics are more effective when taken together

Front 57

Antagonism

Back 57

Antibiotics taken in tandem are less effective than when taken alone

Front 58

Microdilution plate

Back 58

Used in broth dilution test to determine MIC using many different wells with varying concentrations of antibiotics