Idit Exam 3 - Walters - Miscellaneous Beta Lactams And Other Inhibitors Of Cell Wall Synthesis

Front 1

What is the structure of Aztreonam

Back 1

Monobactam with a stand alone beta lactam ring

Front 2

Is Aztreonam active against G (-) or G(+)?

Back 2

Only G(-)

Front 3

Is Aztreonam resistant or susceptible to beta-lactamases in G(-) organisms?

Back 3

Resistant

Front 4

What is the mechanism of Aztreonam?

Back 4

Binds penicillin binding protein-3 (PBP-3) of G- bacteria --> creates long unstable filamentous bacteria that lyse

Front 5

How is aztreonam excreted?

Back 5

Excreted unchanged in urine

Adjust dose for renal failure

Front 6

Can Aztreonam cross the BBB?

Back 6

Yes, it can cross only if inflamed meninges

Front 7

What does Vancomycin treat?

Back 7

MRSA

Nonresistant Staph (MSSA) if pt is allergic to beta-lactams

Front 8

Is Vancomycin absorbed orally?

Back 8

No, that's why you administer it via IV for a systemic effect

Front 9

Why would a patient take Vancomycin orally?

Back 9

For local infection for pseudomembranous colitis

Front 10

What is the mechanism of Vancomycin?

Back 10

Binds to and prevents removal of D-ala attached to NAM in peptidoglycan

Note: different from PCN/cephalosporin

Front 11

What are 3 side effects of Vancomycin?

Back 11

1. Ototoxicity
2. Nephrotoxicity
3. Red man syndrome

Front 12

Describe the mechanism of Red Man syndrome.

Back 12

If given rapid IV --> Histamine is released --> Vasodilation --> Flushing of upper body & face, hypotension, tachycardia, and shock

Front 13

Is Bacitracin static or cidal?

Back 13

Cidal

Front 14

Is Bacitracin good for Gram (+/-)? Cocci, bacilli, spirochete, etc.?

Back 14

Gram+
Cocci and bacilli

Front 15

What is the mechanism of Bacitracin?

Back 15

Bacitracin complexes with pyrophosphate --> Prevents dephosphorylation of bactoprenol --> Inhibit cell wall synthesis

**Bactoprenol is a lipid carrier that brings NAG/NAM complex to outside of cell. Here it can attach to growing end of peptidoglycan chain, but in order to do so, bactoprenol must be dephosphorylated first.

Front 16

What is a side effect of Bacitracin?

Back 16

Nephrotoxicity

Front 17

What is Bacitracin used for?

Back 17

Topical - minor cuts, scrapes
Opthalmic - ulcerative blepharitis, bacterial conjuctivitis (due to various G+/G- organisms)

Front 18

What is Fosfomycin used for?

Back 18

Short course treats uncomplicated UTI in WOMEN

Front 19

What is the mechanism of Fosfomycin?

Back 19

Complexes with pyrophosphate --> Blocks addition of phosphoenolpyruvate to UDP-N-acetylglucosamine --> Inhibit cell wall synthesis

*Adding phosphoenolpyruvate to UDP-NAG is the 2nd step in the synthesis of Park-Nucleotide (UDP-N-acetylmuramyl pentapeptide).

Front 20

How is Televancin related to Vancomycin?

Back 20

Televancin is a semisynthetic derivative of vancomycin

Front 21

Route for Televancin?

Back 21

IV

Front 22

Is Televancin a protein, lipid, etc?

Back 22

It is a lipoglycopeptide

Front 23

Is Televancin cidal or static?

Back 23

Cidal

Front 24

What is Televancin used for?

Back 24

1. Complicated skin and skin structure infections

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

Front 25

What is the two ways Televancin works?

Back 25

1. Binds to D-ala terminus to prevent removal (like Vancomycin)

2. Disrupts membrane potential --> increases membrane permeability --> further destabilizes cell membrane

Front 26

What are the side effects of Televancin?

Back 26

NVD (nausea, vomiting, diarrhea)
Taste distrubance
Foamy urine

Front 27

Why should you be cautious of giving Televancin to pregnant women?

Back 27

Potentially teratogenic