Penecillin

Question 1

structure of penicillin

Answer 1

house with a garage

4-member B-lactam ring next to 5-member sulfa ring

Question 2

B-lactam MOA

Answer 2

bind the cell wall and inhibit cell wall/peptidoglycan synthesis (penicillin binding proteins). inhibits transpeptidase which makes cross links in peptidoglycan.

Question 3

B-Lactam:
Bacteriocidal or Bacteriostatic?
concentration dependent or time dependent?
Elimination half-life?
Elimination route (primarily)?

Answer 3

Bacteriocidal (except against entercoccus species)

Time-dependent

Question 4

Which B-lactams aren’t eliminated by the kidney?

Answer 4

nafcillin, oxacillin,

ceftriaxone, cefoperazone

Question 5

Most common mechanism of B-lactam resistance?

Answer 5

B-lactamase (hydrolyzes B-lactam ring)

Question 6

B-lactamase activity in gram pos?

Answer 6

destroy B-lactams extracellularly

Question 7

B-lactamase activity in gram neg?

Answer 7

destroy B-lactams in the periplasm (between inter and outer membrane) after B-lactams enter through porins

Question 8

Natural penecillins examples (with attributes)?

Answer 8

IV:
Penicillin G (still used)
Benzapine (long-lasting, used 1x/week for latent syphilis)
Procaine (short acting)
Oral:
Penicillin VK (more readily absorbed)

Question 9

Bacteria treated by Natural Penicllins?

Answer 9

Gram+ = Group Strep and viridians strep
gram- cocci = neisseria spp
Anaerobes = clostridium (not C.Diff)
syphilis

Question 10

Penicllinase-resistant Penicllin examples?

Answer 10

IV: Nafcillin, Oxacillin, Methicillin (Ox and Meth not used)
Oral: Dicloxacillin (not absorbed well orally)

Question 11

Bacteria treated by Penicillinase-resistant Penicillins?

Answer 11

Gram+ = MSSA (Methicilline susceptible staph aureus)

made specifically for staph aureus’s penicillinase

Question 12

What gene causes staph aureus to be resistant to penicillinase-resistant penicillin (MRSA)? And how does it convey resistance? What is only drug that can treat MRSA?

Answer 12

mecA gene. changes the binding site.

Ceftaroline.

Question 13

Aminopenicillins: Why created? examples?

Answer 13

Gram neg activity (especially for Ecoli)
IV: Ampicillin
Oral: Amoxicillin (Ampicillin can be given but it isn’t)

Question 14

Bacteria treated by Aminopenicillins?

Answer 14

Gram+ = same as penicillin, but better with enterococci. Only drug that treats Listeria monocytogenes (Gram+)
Gram- = proteus mirabilis, Ecoli (most), salmonella, shigella, H.flu

Question 15

Carboxypenicillins: why made? examples?

Answer 15

Gram neg bacteria

IV: Ticarcillin (only available in combination)

Question 16

Bacteria treated by Carboxypenicillins?

Answer 16

Gram+ = carboxy group diminishes gram+ effects, so none
gram- = pseudomonas aeruginosa (hospital-acquired illness)

Question 17

Ureidopenicillins: why made? examples?

Answer 17

gram neg bacteria treatment but still retaining some gram pos treatment ability
IV: Piperacillin (only available in combo with tazobactam)

Question 18

Bacteria targeted by Ureidopenicillins?

Answer 18

Gram- = pseudomonas aeruginosa (also enterbacter, klebsiella, and serratia marcescens)
Anaerobes (very often used on anaerobes)

Question 19

B-lactamase inhibitor action?

Answer 19

irreversibly bind catalytic site of B-lactamase

Question 20

B-lactamase inhibitor/penicillin combos?

Answer 20

IV: ampicillin-sulbactam
ticarcillin-clavulanate (no longer available)
Piperacillin-tazobactam
Oral: amoxicillin-clavulanate

Question 21

bacteria treated with B-lactamase inhibitor combos

Answer 21

gram+ = non-MRSA staph aureus
gram- = H.flu, moraxella catarrhalis
Anaerobes: bacteroides spp

Question 22

What needs to happen to get adequate penicillins into CSF?

Answer 22

ONLY n the presence of inflamed meninges with high-dose IV administration

Question 23

clinical uses of natural penicillins?

Answer 23

anything that is penicillin susceptible like strep
syphilis
endocarditis prophylaxis

Question 24

clinical uses of penicllinase-resistant penicillin?

Answer 24

MSSA

Question 25

Aminopenicillins clinical use?

Answer 25

Resp tract infections Entercoccal infections Listeria monocytogenes endocarditis prophylaxis

Question 26

Carboxypenecillin and ureidopenecillin clinical uses?

Answer 26

gram neg aerobic bacterial infections (pneumonia, bacteremia, UTIs) empiric therapies pseudomonas aeruginosa (especially piperacillin)

Question 27

Adverse effects of penicillin?

Answer 27

(more with IV) ranges from rash to anaphylaxis and death | ABs made to metabolic by-products

Question 28

Neurologic adverse effects?

Answer 28

irritability, jerking, seizures, confusion

Question 29

Hematological adverse effects?

Answer 29

leukopenia, neutropenia, thrombocytopenia | usually from prolonged therapy, reversible upon stopping

Question 30

Adverse GI effects?

Answer 30

increased LFTs, nausea, vomiting, diarrhea, pseudomembranous colitis (diarrhea from C.Diff)

Question 31

Adverse Renal effects?

Answer 31

Interstitial nephritis=damage to renal tubules leading to renal failure