Cell wall Active Agents

Question 1

Are cell wall synthesis inhibitors more effective on gram positive or gram negative? are they bactericidal or static? do they penetrate BBB well? oral administration? hepatic clearance?

Answer 1

1. Gram+
2. Bactericidal
3. Poor penetration
4. Oral
5. No, renal clearance

Question 2

Is bacitracin only for topical application? why or why not?

Answer 2

Yes- poorly absorbed and potential for sever nephrotoxicity

Question 3

What drug is rapidly bactericidal for dividing bacteria by binding D-ala-Dala terminus of pentapeptide? what is its structure? how do we administer? spectrum?

Answer 3

1. vancomycin
2. glycopeptide [teicoplanin and dalbavancin]
3. IV administered, poor absorption orally but great distribution
4. narrow, gram + most MRSA

Question 4

What are the 2 mechanisms of vancomycin resistance?

Answer 4

– VRE: Enterococci vanA, vanB or vanC genes;
bacteria make different cell wall subunits with
reduced binding to vancomycin
– VRSA: S. aureus overexpress D-ala – D-ala
(normal substrate = competitor, binds up drug)

Question 5

What is vancomycin synergistic with?

Answer 5

aminoglycosides

Question 6

What are the 4 major classes of B lactam antibiotics?

Answer 6

penicillins
cephalosporins
carbapenems
monobactams

Question 7

Are beta lactam antibiotics bactericidal? what does this mean?

Answer 7

Yes- must be dividing

Question 8

What gives beta lactam antibiotics their pharmacological properties?

Answer 8

R amino groups

Question 9

Beta lactams have a wide distribution except where?

Answer 9

CNS

Question 10

Beta lactams are renal excreted and not metabolized…what are the 2 exceptions?

Answer 10

nafcillin and imipenem

Question 11

Do beta lactams work on spirochetes-

Answer 11

yes…t. pallidum

Question 12

Besides production of beta lactamases what are 3 other methods of resistance to beta lactam antibiotics?

Answer 12

1. alter target PBPs
2. alter outermembrane proteins
   3, increase efflux pump activity (porins)

Question 13

What type of allergic reaction amongst beta lactam antibiotics causes rash? is it common?

Answer 13

1. delayed

2. 80-90% of all allergic reactions

Question 14

Is pen G or PEn V acid labile? orally administered?

Answer 14

1. Pen G

2. Pen V- absorption is 65% vs. 30 for penG

Question 15

What does procaine and benzathine do to Pen G IM?

Answer 15

water-insoluble, slow release into bloodstream

Question 16

What is steven-johnson syndrome?

Answer 16

Stevens-Johnson syndrome is a rare, serious disorder of your skin and mucous membranes. It’s usually a reaction to a medication or an infection. Often, Stevens-Johnson syndrome begins with flu-like symptoms, followed by a painful red or purplish rash that spreads and blisters. Then the top layer of the affected skin dies and sheds.

Question 17

What 4 drugs are in the penicillinase resistant category? are they acid stable?

Answer 17

methicillin
oxacillin
cloxacillin
nafcillin

Yes acid stable

Question 18

What penicillinase resistant antimicrobial sometimes causes interstitial nephritis? hepatitis?

Answer 18

methicillin

oxacillin

Question 19

Can Aminopenicillins, carboxypenicillins and

ureidopenicillins be destroyed by beta lactamases? amino penicillin examples? which one is not effected by food intake?

Answer 19

1. Yes!!!
2. [ampicillin, amoxicillin]
3. amoxicillin

[used for E.Coli, H.influenzae, Salmonella, Shigella]

Question 20

What drug is used for prophylaxis against bacterial endocarditis?

Answer 20

amoxicillin

Question 21

How are carboxypenicillins administered? ureidopenicillin?

Answer 21

parenteral for both

Question 22

What are ureidopenicillins used for? often in combo with what?

Answer 22

1. Reserved for serious systemic infections caused
   by Klebsiella or Pseudomonas infections
2. aminoglycoside

Question 23

What are the 3 beta lactamase inhibitors?

Answer 23

1. clavulanic acid, sulbactam, tazobactam

Question 24

What are the most widely used hospital prescribed antibiotics

Answer 24

cephalosporins

Question 25

Are cephalosporins used topically

Answer 25

No- orally, IV or IM

Question 26

How is bacterial resistance brought about with cephalosporins?

Answer 26

1. induce Amp C (cephalosporinase)

2. Low affinity PBPs

Question 27

What cephalosporin generation is Anti-pseudomonal High resistance to -lactamases; useful for treating
Enterobacter and penicillin-resistant streptococci?

Answer 27

4th cefepime

Question 28

What cephalosporin generation is Broadest spectrum against gram+ cocci (surgical
prophylaxis); effective against gram- bacilli

Answer 28

1st cefazolin

Question 29

What cephalosporin generation is Only group with significant activity against anaerobes?

Answer 29

2nd cefuroxime

Question 30

What cephalosporin generation is Anti-pseudomonal and -pneumococcal; serious graminfections
such as meningitis, pneumonia, gonorrhea
– Most widely used treatment in children / infants with
moderate to severe infections

Answer 30

3rd Cefotaxime

Question 31

Do imipenem have beta lactam ring? can they penetrate gram-? narrowest activity of all beta lactam drugs?

Answer 31

1. Yes, and bind more efficiently.
2. yes
3. broadest (not for MRSA or VRE)

Question 32

Do carbapenems antagonize tidal effects of pens and cephs?

Answer 32

yes- because they induce beta lactamases that inactivate pens and cephs

Question 33

How are carbapenems administered? metabolized and inactivated? what are they administered with?

Answer 33

1. parenteral
2. Yes imipenem is renal
3. cilastatin

Question 34

Can monobactams penetrate BBB?

Answer 34

yes when inflamed

Question 35

What are monbactams limited to to treat?

Answer 35

gram - areobes including pseudomonas.

Question 36

How is daptomycin administered? eliminated?

Answer 36

1. IV

2. Renal elimination

Question 37

What does daptomycin treat that makes it awesome?

Answer 37

VREF and MRSA!!!