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Flashcards in 8.3 Deck (20):
1

What is the mechanism of Carbapenems?

Small molecules – use porins to gain access to periplasma of G-
Structure resistant to most beta-lactamases
Has broad range for PBPs from different bacteria

2

How can bacteria become resistant to Carbapenems?

Loss of production of porins on outer membrane
Overproduction of efflux pump
Altered PBPs – do not recognize carbapenems
Produce extremely powerful beta-lactamases – able to cleave carbapenem

3

What is the coverage of Carbapenems?

G+ (staph, strep) listeria, HEN, pseudomonas

4

Why is Imapenem given with elastin?

imipenem alone is destroyed quickly in the kidney- to prolong activity of med, need to inhibit enzyme (here Cilastatin)

5

What is the coverage of meropenem and doripenem?

Same as imipenem-
G+ (staph, strep) listeria, HEN, pseudomonas

6

What makes ertipentm different from the rest of the Carbapenems?

No pseudomonas, no Acinetobacter
qDay dosing

7

What are monobactams?

G-, fully synthetic
1 beta-lactam ring (not really a true b-lactam)
Can use with pts who have B-lactam (PCN) allergy

8

What is the coverage of monobactams?

G-
Intermediate coverage for pseudomonas

9

What are the toxicities of monobactams?

Relatively safe
Rash, Toxic epidermal necrolysis (rare), may induce eosinophilia
No allergic cross reactions between aztreonam and other beta-lactams okay to use in pts with PCN allergy

10

What is the mechanism of Vanc?

Attack cell wall
Large- can't pass through porins
NAG/NAM backbone liked by peptide side chains, last 2 AAs in the chain are Alanine- Vanc covers these 2 AAs, this keeps PBP from recognizing chains, therefor cross-linking between backbones is disrupted, damaging cell wall

11

What is the coverage of glycopeptides?

G+: nearly all staph (and MRSA), strep, anaerobic G+ (c. diff)

12

What are examples of glycopeptides?

Vancomycin
Telavancin

13

What are SA of glycopeptides?

Infusion related syndrome – “Red man syndrome” = “Red neck syndrome”
Phlebitis
Ototoxicity – associate with peak level (25-50mcg/mL)
Nephrotoxicity – associate with trough level (10-20mcg/mL)

14

What is the mechanism of televancin?

Promotes binding to bacterial cell membranes --> pore formation --> cell leakage

15

What does daptomycin cover?

Active against G+ including MRSA and some VRE
No G- activity
Poor activity in lungs  not to treat PNA

16

What is the MOA of daptomycin?

Lipid portion insert into baterial membrane --> form ion-conducting channel --> lysis

17

What is the indications for daptomycin?

Only use for SSTI (skin and soft tissue infection) and bacteremia/endocarditis

18

What are the SA of daptomycin?

Myopathy, especially at higher doses --> check CPK
Phlebitis
Rash
GI

19

What is the mechanism of colistin?

unique; uses electrical charge to expel Ca+ and Mg+ that stabilize bacterial membrane. Once cations displaced, the membrane becomes destabilized, causing cell death.

20

What does colistin cover?

Pseudomonas
E Coli
H flu
Klebsiella