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Flashcards in L2: Antimicrobial Agents Deck (144)
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1

Antibiotics and antimicrobial agents are different from disinfectants how?

They are specific for certain bacteria or microbes

2

Many antibiotics come from what?
What does this help explain?

Natural compounds made by bacteria or fungi to gain an evolutionary advantage in natural environments.

High resistance to some antibiotics since bacteria have been exposed to these compounds for millions of years

3

3 characteristics of the ideal antibiotic

1. Target a variety of pathogens but spare normal flora
2. Prohibit rapid development of resistance
3. Selective for bacteria and does not damage host

4

What is the ideal antibiotic?

No such thing

5

Antibiotics are generally targeted against what?

Systems in all bacteria

6

The broader the spectrum of an antibiotics, the more likely what will happen?

The antibiotic will be more likely to attack normal flora

7

Do all antibiotics have resistance somewhere?

Yes

8

Limiting resistance to a drug has more to do with what? 2

1. Prescribing practices of physicians
2. compliance of patients

9

Are all antibiotics toxic to the host?
Why or why not?

Yes
Since mitochondria are evolutionarily related to bacteria, many broad spectrum drugs affect mitochondria function

10

What are 4 of the main adverse effects of antibiotics?

1. Allergic reactions (penicillin)
2. Toxic (aplastic anemia, ototoxicity)
3. Suppression of normal flora: (colon)
4. Antimicrobial resistance

11

Antibiotics are split into what two categories?

1. Bacteriostatic
2. Bactericidal

12

What is difference between bacteriostatic and bactericidal?

bacteriostatic = inhibit growth
bacteriocidal = kill

13

Bacteriostatic drugs rely on what to eliminate pathogen?

Host immunity

14

Bactericidal drugs are useful when?

situations when host defenses cannot be relied upon to control the pathogen

15

What are the five main targets of an antibiotic?

1. Cell wall
2. protein synthesis
3. nucleic acid synthesis
4. metabolic pathways
5. Cytoplasmic membrane

16

Which is the least toxic target of an antibiotic?
Why?

Cell wall
Mitochondria do not make peptidoglycan so it doesn't attack them.

17

What is one side effect of a cell wall antibiotic?

Allergic reaction to peptidoglycan fragments

18

In terms of protein synthesis what is targeted in antibiotics? What will also be targeted?

Bacterial ribosomes
Mitochondrial ribosomes are inhibited leading to side effects

19

How useful are the antibiotics against nucleic acids?

Not very because there aren't many conserved bacterial enzymes.

20

How useful are antibiotics against metabolic pathways?

Average, there are some unique bacterial metabolic enzymes

21

How are antibiotics used against cytoplasmic membranes?
WHy?

In a topical manner

Bacterial membranes are similar to eukaryotic membranes.

22

3 parts of cell wall synthesis?

1. Cell wall subunits are made in cell cytoplasm
2. Bactoprenol transports the subunits from inside the cell to ouside the cell
3. Penicillin binding proteins link the subunits together into the existing cell wall

23

What anti-biotic attacks cytoplasmic synthesis of cell wall subunits?

Fosfomycin
Cycloserine

24

What anti-biotic attacks BACTOPRENOL and the transport of subunits?

Bacitracin

25

What do Beta-lactams do?

Attack PBP

26

What antibiotic is used against crosslinking?

Vancomycin

27

Beta-lactams contain a 4 membered ring called the what?
What does it mimic?

lactam ring

the terminal D-ala-D-ala of peptidoglycan side chains.

28

Where can beta-lactams bind?

transpeptidases and carboxypeptidases and inhibit their function.

29

Transpeptidases and carboxypeptidases are collectively known as what?

penicillin binding proteins or PBPs

30

inhibition of PBP inhibits what?

cross-linking of peptidoglycan chains weakening the mesh