Vancomycin

Question 1

What produces Vancomycin via fermentation?

Answer 1

Streptomyces orientalis

Amycolatopsos orientalis

Question 2

How does Vancomycin work?

Answer 2

Inhibits Gram + cell wall biosynthesis

Question 3

How does Vancomycin inhibit?

Answer 3

Binds to side chain D-alanyl terminus before cross linking

Question 4

Are gram - bacilli or mycobacteria susceptible to Vanco?

Answer 4

No

Question 5

What level of MIC is needed to be considered susceptible for Vanco?

Answer 5

4ug/mL

Question 6

What is the last line of defense against hospital aquired multidrug resistant staph and strep infections?

Answer 6

Vancomycin

Question 7

What mutation is causing the resitance to vancomycin?

Answer 7

Peptidoglycan wall formation switch from D-Ala D-Ala to D-Ala D-lactate

Question 8

Side effect of Vanco?

Answer 8

Hypersensitive red skin rash

Potential anaphylaxis

Question 9

Toxicity to Vanco?

Answer 9

Nephrotoxicity due to high concentration

Question 10

How many membered are the macrocyclic lactones?

Answer 10

14 membered

Question 11

How are macrolide antibiotics produced?

Answer 11

Sequential addition of proprionate groups

Question 12

pKa of amine in erythromycin?

Answer 12

8.8

Question 13

What is translocation?

Answer 13

Peptodyl-tRNA is shifted from the A site to the P site

Question 14

How do macrolides work?

Answer 14

Binding reversibly to the P site of the bacterial ribosome

Question 15

Where do macrolides accumulate?

Answer 15

Leukocytes

Question 16

Why is it good that macrolides accumulate in leukocytes?

Answer 16

They are transported into the site of infection

Question 17

Macrolide binding mainly invovles what?

Answer 17

Bacterial 23S RNA

Question 18

Function of lactone ester hydrolase?

Answer 18

Induce to degrade macrolides via hydrolysis of macrocycle

Question 19

RNA methylase will have what effect on resistance of erythro?

Answer 19

Inhibits binding of macrolides to 50S subunit

Question 20

Mutation of adenine to gunanine at site A2058 results in what?

Answer 20

Reduction in binding of erythro and clarithromycin to 23 S ribosomal RNA

Question 21

What will the result of a drug efflux pump be?

Answer 21

Resistance to erythro

Question 22

Which organisms exhibit intrinsic resistance to macrolides?

Answer 22

Pseudomonas spp.

Enterobacter spp.

Question 23

In macrolyides acidic conditions affect which group?

Answer 23

6-OH group

Question 24

If the macrolide group 6-OH is transformed into a ketal what is the result?

Answer 24

It’s inactive

Question 25

What is a way to work around the acidity problem with macrolides?

Answer 25

USe Clarithromycin which has a 6-OCH3 that blocks ketal formation

Question 26

Besides Clarithromycin what is another alternative to skirt the acid problem of macrolides?

Answer 26

Azithromycin

Question 27

Why with Azithromycin negate the acid problem?

Answer 27

Replaces the C-9 ketone makine ketal formation impossible

Question 28

Main route of erythromycin metabolism?

Answer 28

Demethylation in the liver

Question 29

Main elimination route of erythro?

Answer 29

Bile | Small part in urine

Question 30

Half life of erythro?

Answer 30

1.5 hours

Question 31

Erythro and Clarithro effect on CYP3A?

Answer 31

Bind and inhibit

Question 32

Dirithromycin effect on P450 isozymes?

Answer 32

Reduced capacity to inhibit

Question 33

Macrolides that doesn't have any potential drug interactions?

Answer 33

Azithromycin

Question 34

Effect of macrolides on GI system?

Answer 34

Stimulate GI motor activity and can cause vomiting, gastric cramps, and abdominal pain

Question 35

two rare occurances due to macrolide use?

Answer 35

Stevens-Johnson syndrome | Toxic epidermal necrolysis

Question 36

Long term use of macrolides can cause what reversible problem?

Answer 36

Cholestatic hepatitis | Gone after termination of drug use

Question 37

What can erythro effect in children whose mothers took it while in late stages of pregnancy?

Answer 37

Pyloric stenosis

Question 38

Where is erythro most effectively absorbed?

Answer 38

Tissues and phagocytes

Question 39

What is erythromycin estolate?

Answer 39

Prodrug of erythromycin

Question 40

Benefit of Erythromycin estolate?

Answer 40

More lipophilic | Increase oral absorption

Question 41

What is erythromycin estolate used to treat?

Answer 41

Group A beta hemolytic strep Primary Syphillis Alpha hemolytic strep

Question 42

What is erythromycin ethyl succinate?

Answer 42

Prodrug of erythromycin

Question 43

What is more effective against Haemophilis influenzae than clarithromycin

Answer 43

Clarithromycin metabolite 14-(R) hydroxy

Question 44

How many members in Azithromycin ring?

Answer 44

15, due to removal of Carbon 9 to prevent ketal formation

Question 45

Half life of Azithromycin?

Answer 45

68 hours

Question 46

Which elements can interefere with Azithromycin absorption into tissues?

Answer 46

MAgnesium and aluminum

Question 47

Major route of elimination for Azithromycin?

Answer 47

Biliary

Question 48

What bacteria does Azithromycin kill better than eyrthro or clarithro?

Answer 48

Gram -