Antibiotics II: Inhibitors of Cell Wall Synthesis

Question 1

Subclasses of beta-lactam antibiotics

Answer 1

Penicillins
Cephalosporins
Carbapenems
Monobactams

Question 2

Beta-lactam _____ is essential for activity

Answer 2

Structure

Question 3

Beta-lactam ring has a high affinity for bacterial ______

Answer 3

Penicillin binding proteins (PBPs)

Question 4

Beta-lactams are bacteriostatic/Bactericidal and ____ dependent

Answer 4

Bactericidal; time dependent

Question 5

Beta-lactams inhibit the ____ step of cell wall synthesis

Answer 5

Final (cross linking of NAM NAG polymers)

Question 6

Inhibition of PBPs by beta-lactams is reversible/irreversible

Answer 6

Irreversible

Question 7

PBP inhibition activates ____, causing disassembly of cell wall leading to cell lysis or apoptosis

Answer 7

Autolysins

Question 8

What is the most common drug allergy?

Answer 8

Penicillins

Question 9

What enzyme inactivates penicillins?

Answer 9

Beta-lactamase

Question 10

Anti-staphylococcal cell-wall inhibitor

Answer 10

Nafcillin

Question 11

Emergence of methicillin-resistance (MRSA) is due to ______

Answer 11

Altered PBPs with lower binding affinities

Question 12

Aminopenicillin drug

Answer 12

Amoxicillin

Question 13

How is coverage of amoxicillin different than that of penicillin?

Answer 13

Spectrum similar to penicillin but effective against some G- bacilli too

Question 14

Common uses for amoxicillin

Answer 14

Sinusitis
Otis media
Lower respiratory infections

Question 15

Extended-spectrum/anti-pseudomonal penicillin drug

Answer 15

Piperacillin-tazobactam (Zosyn)

Question 16

Clavulanate function in amoxicillin-clavulanate (Augmentin)

Answer 16

Beta lactamase inhibitor; Protects amoxicillin from inactivation by beta-lactamases in G- bacteria

Question 17

Penicillins have poor/good oral absorption

Answer 17

Poor (can cause diarrhea)

Question 18

Penicillins have long/short half lives so must be given ____

Answer 18

Short; frequently (3-6x/day)

Question 19

Penicillins are excreted by _____

Answer 19

Renal secretion

Question 20

Adverse reactions of penicillins

Answer 20

Very safe class of antibiotics
Mild NVD
Amoxicillin can cause a maculopapular rash

Question 21

True penicillin allergy is a Ig_ mediated hypersensitivity

Answer 21

IgE

Question 22

True penicillin allergies cause a _____ rash

Answer 22

Urticarial

Question 23

Cephalosporins are grouped by ____

Answer 23

Generations

Question 24

Each Cephalosporin generations increases

Answer 24

Activity against G- and anaerobes
Resistance to inactivation by beta-lactamases
Penetration across BBB into CNS

Question 25

First generation cephalosporin

Answer 25

Cefazolin

Question 26

Second generation cephalosporin

Answer 26

Cefoxitin

Question 27

Third generation cephalosporin

Answer 27

Ceftriaxone

Question 28

Fourth generation cephalosporin

Answer 28

Cefepime

Question 29

Fifth/advanced generation cephalosporin

Answer 29

Ceftaroline

Question 30

Drug of choice for bacterial G- meningitis

Answer 30

Ceftriaxone

Question 31

Only beta-lactam that is active against MRSA

Answer 31

Ceftaroline

Question 32

Prototype carbapenem drug

Answer 32

Imipenem-cilistatin

Question 33

Carbapenems are highly susceptible/resistant to inactivation by beta lactamases

Answer 33

Highly resistant

Question 34

Why is imipenem combined with cilastatin?

Answer 34

To block renal inactivation

Question 35

Uses for carbapenems

Answer 35

Multi-drug resistant infections
Anaerobic and mixed infections

Question 36

Prototype monobactam drug

Answer 36

Aztreonam

Question 37

Monobactams are only active against ____

Answer 37

G- aerobes

Question 38

Monobactams are/are not cross-reactive with other beta-lactams

Answer 38

Are not cross reactive (can be given even if pt has severe penicillin allergy)

Question 39

Aminoglycosides are ____toxic

Answer 39

Nephrotoxic