Antibiotics and Resistance - Part 2 Flashcards Preview

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Flashcards in Antibiotics and Resistance - Part 2 Deck (62):
1

Name the first streptogramin antibiotic to be released

Synercid

2

Describe the structure of the first streptogramin antibiotic synercid

A combination of two cyclic peptides - quinupristin and dalforpristin

3

Streptogramin antibiotics are distantly related to which antibiotic group?

The macrolides

4

How do streptogramin antibiotics such as Synercid act?

They block protein synthesis by attaching to the 50S portion of the ribosome

5

Against which bacteria are streptogramins effective against?

A broad range of gram-positive bacteria

6

The oxazolidinones are a new class of antibiotics developed in response to...

Vancomycin resistance

7

How do oxazolidinones act?

They act on the ribosome, inhibiting protein synthesis

8

What is different in the way oxazolidinones act on the 50S ribosome compared to other antibiotics discussed?

They act close to the point where it interfaces with the 30S subunit

9

The oxazolidinones are totally synthetic which may

make resistance slower to develop

10

Give an example of an oxazolidinone and its function

Linezolid - used mainly to combat MRSA

11

What is the mode of action of pleuromutilin antibiotics?

Interfere with protein synthesis

12

What is the first pleuromutilin antibiotic to be approved?

Retapamulin

13

What is a limitation of Retapamulin which is a pleuromutilin antibiotic?

It is limited to topical use

14

What is pleuromutilin effective against?

Gram positive bacteria including MRSA

15

A new class of antibiotics developed in recent years...

Lipopeptides

16

Give an example of a lipopeptide that is effective against gram positive bacteria including MRSA infections

Daptomycin

17

Daptomycin is produced by a...

Streptomycete

18

Daptomycin is approved for what?

For certain skin infections

19

What is the apparent mechanism of daptomycin which is a lipopeptide antibiotic

To attack the membrane of the bacterial cell

20

Give an example of a lipopeptide antibiotic which is used for gram negative bacteria

Polymyxin B

21

Infections caused by Pseudomonas Bacteria can be treated with

Polymyxin B which is a lipopeptide
By attacking the membrane of the bacterial cell

22

Give an example of a rifamycin antibiotic

Rifampin

23

How do the rifamycin class of antibiotics such as rifampin work?

They are nucleic acid synthesis inhibitors - work by inhibiting the synthesis of mRNA

24

Rifampin are structurally related to...

The macrolides

25

What is a valuable characteristic of rifampin?

The ability to penetrate and reach therapeutic levels in cerebrospinal fluid and abscesses

26

What is the most important use of rifampin?

Against mycobacteria in the treatment of tuberculosis and leprosy

27

What is the method of action of the quinolones and fluoroquinolones?

Nucleic acid synthesis inhibitors - inhibits an enzyme needed for the replication of DNA
DNA gyrase

28

The first quinolone group of antimicrobials is

Nalidixic acid

29

Nalidixic acid has a limited use, explain.

Only application is for urinary tract infections

30

Why were the quinolones of use?

Allowed the development of the synthetic quinolones known as the fluoroquinolones

31

When were the fluoroquinolones developed from the quinolones?

In the 1980's

32

Fluoroquinolones have a ______ spectrum of activity compared to quinolones

Broader

33

Name two of the earliest generation fluoroquinolones

Norfloxacin and ciproflaxacin

34

Name two of the newer groups of fluoroquinolones

Gemifloxacin and moxifloxacin

35

What is a major issue with fluoroquinolones?

Resistance can develop rapidly, even during the course of a treatment

36

Give an example of a group of antimicrobials which kill by the competitive inhibition of essential metabolites

Sulfonamides

37

Why is folic acid important in microbes?

Folic acid is an important co enzyme needed for the synthesis of proteins, DNA and RNA

38

How do sulfonamides act?

They are structurally similar to the folic acid precursor called para-aminobenzoic acid (PABA)
Competitively bind with the enzyme meant for PABA
Block folic acid production

39

Give an example of drug-synergism

TMP-SMZ = trimethoprim and sulfamethoxazole

40

What is drug synergism ?

Drug synergy occurs when drugs can interact in ways that enhance or magnify one or more effects

41

The TMP-SMZ combination has what advantage?

Broader spectrum of activity and reduces the emergence of resistant strains

42

How do most antifungal drugs work?

By targeting the sterols in the plasma membrane

43

In fungal membranes, the principle sterol is?

Ergosterol

44

In human membranes, the principle sterol is?

Cholestrol

45

How does inhibition of ergosterol biosynthesis of fungal cells cause death?

The membranes become excessively permeable

46

Name the most commonly used member of the antifungal polyene group.

Amphotericin B

47

What is amphotericin B used for?

Fungal diseases - histoplasmosis, coccididomycosis and blastomycosis

48

Azoles are widely used anti____ drugs

antifungal

49

What were the first azoles?

The imidazoles

50

Give two examples of the imidazoles

Clotrimazole and miconazole

51

Azoles can be used without prescription for

topical application such as athlete's foot

52

What is an advantage of triazole as an antifungal?

It is less toxic, and more water soluble

53

The low toxicity and water solubility of triazole means that it is

more effective against systemic infections

54

What are systemic infections?

Infections that affect the entire body

55

Give two examples of triazoles

Fluconazole and itraconazole

56

The allylamines work by...

Inhibiting the biosynthesis of ergosterols

57

Give two examples of allylamines

Terbinafine and naftifine

58

Other than the plasma membrane of fungal cells, what is another primary target for antifungal agents?

The beta-glucan of the cell wall

59

What type of antifungals inhibit the biosynthesis of glucans?

The echinocandins

60

The echinocandins inhibit the biosynthesis of glucans, what does this result in?

An incomplete cell wall which then results in cell lysis

61

Other than targeting the fungal cell membrane or the fungal cell wall, what else can be target by antifungals?

Inhibition of nucleic acids

62

Give an example of an antifungal which interferes with the biosynthesis of RNA and therefore disrupts protein synthesis

Flucytosine