Walters- Carbapenems, Misc. Beta Lactams and Other Inhibitors of CW synthesis

Question 1

_____ are the broadest spectrum of beta lactams. They are good for treating gram + and gram - organisms, and_____ and are reserved for resistant infection. They have little cross resistance and enter G by different route

Answer 1

carbapenems; anaerobes;

Question 2

Original carbapenem was ___ with cilastatin via IV/IM. Cilastatin inhibits ____

Answer 2

imipenem; dehydropeptidase –> in kidney proximal tubules that normally metabolizes imipenem. Inhibiting this enzyme increaeses levels of imipenem and prevents generation of a nephrotoxic metabolite.

Question 3

what are the side effects of carbapenems

Answer 3

1. nausea
2. vomiting,
3. seizures

Question 4

What are the carbapenems

Answer 4

1. meropnem
2. ertapenem
3. doripenem

Question 5

Which carbapenem do you take once a day

Answer 5

ertapenem

Question 6

this carbapenem is taken parenterally for complicated intra abdominal infections and UTIs. It is not to be used for any type of pneumonia due to increased risk of death and decrease cure rates compared to imipenem/cilastatin

Answer 6

doripenem

Question 7

what are general uses of carbapenem?

Answer 7

1. UTIs
2. bone, joint, and skin infections
3. intra abdominal and gynecological infections,
4. bacterial septicemia

Question 8

____ is emerging in long term care facilities and nursing homes, particularly in pts on ventilators, where elderly are most affected.

Answer 8

CRKP (carbapenem klebsiella pneumonia)

Question 9

what are drug interactions

Answer 9

decreases levels of valproic acid; therefore increases the risk of seizures

Question 10

what is a monobactam

Answer 10

aztreonam; active only against G- aerobes.

Question 11

what is the mechanism for aztreonam

Answer 11

binds PBP-3 of gram negative bacteria; which creates long unstable filamentous bacteria that lyse. It is excreted unchanged in urine and can cross inflamed meninges.

Question 12

What is vancomycin

Answer 12

IV for MRSA or MSSA if allergic to beta lactase; if given orally it might be for a local effect; but it is generally used to treat pseudomembranous colitis

Question 13

What causes pseudomembranous colitis

Answer 13

C. difficile

Question 14

what is the mechanism for vancomycin

Answer 14

binds to D-ala-D-ala terminus and prevents removal of terminal D-alanine

Question 15

What are side effects of vancomycin

Answer 15

1. Red man syndrome: causes vasodilation due to histamine release. - You get flushing of upper body and face, hypotension, tachycardia, and shock.
2. Ototoxicity: Renal failure –> drug accumulation (can be permanent)
3. Nephrotoxicity: with other nephrotoxic drugs (reversible)

Question 16

Vancomycin is ____drug against gram positive rods and static against gram positive ____

Answer 16

cidal; cocci

Question 17

____ is a semisynthetic derivative of vancomycin

Answer 17

Telavancin

Question 18

Telavancin is a ____ lipoglycopeptide

Answer 18

cidal

Question 19

What are the uses for telavancin

Answer 19

1. complicated skin and skin structure infections

2. hospital acquired and ventilator associated pneumonia from S. aureus.

Question 20

what is the mechanism for telavancin

Answer 20

1. binds D-ala D-ala terminus of NAM pentapeptide and inhibits crosslinking
2. disrupts membrane potential which increases membrane permeability
   - Net effect = lysis

Question 21

what are side effects of telavancin

Answer 21

1. NVD
2. taste disturbance
3. foamy urine
   * potentially teratogenic

Question 22

____ is a lipoglycopeptide for ABSSSI (acute bacterial skin and skin structure infections) from gram + organisms including MRSA

Answer 22

Oritavancin

Question 23

What are the mechanisms for oritavancin

Answer 23

1. binds stem peptide of peptidoglycan precursors (inhibits polymerization
2. binds peptide bridging segments (inhibits crosslinking)
3. Disrupts membrane integrity; increases membrane permeability, cell death (depolarization)

Question 24

what are side effects of oritavancin

Answer 24

1. NVD
2. headache
3. SQ absesses

Question 25

what is oritavancin contradicted with

Answer 25

IV unfractionated heparin for 48 hours after administration bc activated partial thromboplastin time (PTT) test results remain falsely elevated.

Question 26

____ is a _____ semisynthetic lipoglycopeptide for ABSSSI. It binds Dala D ala terminus of peptidoglycan and prevents cross linking (as with vancomycin)

Answer 26

Dalbavancin

Question 27

What are side effects of Dalbavancin

Answer 27

1. naseua
2. diarrhea
3. headache

Question 28

____ is _____ against Gram + cocci and rods.

Answer 28

Bacitracin; cidal

Question 29

What is the mechanism for bacitracin

Answer 29

prevents removal of terminal phosphate group in which you run out of carrier by which you you transport part of nucleotide to carry it ouside of cell wall

Question 30

what is the mechanism of bacitracin

Answer 30

prevents removal of terminal phosphate group by binding with pyrophosphate in which you run out of carrier by which you you transport part of nucleotide to carry it ouside of cell wall

Question 31

Oridinarily, ____ a lipid carrier, would transport the NAG/NAM complex to the outsidee of the cell, but must first be dephosphorylated. But bacitracin prevents this dephospho rylation from happening

Answer 31

bactoprenol

Question 32

what is bacitracin used for

Answer 32

1. topical for minor cuts and scrapes
2. ophthalmic for: ulcerative bleph from S. aureus, epidermis
3. bacterial conjunctivitis due to various G+/G- organisms.

Question 33

What is used for uncomplicated UTIs for women

Answer 33

Fosfomycin

Question 34

what is the mechanism for fosfomycin

Answer 34

inhibits enolpyruvate transferase by blocking the addition of PEP to UDP-N-acetylglucosamine, the 2nd step in the synthesis of the Park Nucleotide. Which results in inhibition of cell wall synthesis