Penicillins

Question 1

What are the 4 types of β-lactam antibiotics?

Answer 1

1. Penicillins
2. Cephalosporins
3. Monobactams
4. Carbapenems

Question 2

Structure of Penicillin

Answer 2

beta-lactam ring + thiazolidine ring

Question 3

Penicillinase

Answer 3

A bacteria that specifically produces against penicillin’s β-lactam ring.

Question 4

How do β-lactam abx kill bacteria?

Answer 4

1. Attack on the cell wall

2. Dysregulation of autolysis

Question 5

β-lactams inhibit a family of enzymes involved in final stage of cell wall synthesis called ________. These enzymes can be detected by the covalent binding of penicillin, _______ ______ _______

Answer 5

transpeptidation or cross linkage. Penicillin Binding Proteins (PBPs)

Question 6

Penicillin Binding Proteins are on Penicillin: T/F

Answer 6

False! They are produced by the bacteria and contribute to resistance by alteration.

Question 7

MRSA arises from PBP’s:T/F

Answer 7

True! Specifically PBP2A doesn’t have an affinity to Methicillin.

Question 8

Autolysis normally digest _________ in a regulated manner.

Answer 8

Peptidoglycan

Question 9

β-lactam abx lead to _______ of ______ resulting in cell wall digestion and lysis of bacterial cell.

Answer 9

dysregulation; autolysins

Question 10

3 Major Mechanisms of β-Lactam Resistance by Bacteria

Answer 10

1. Inactivation of abx by a bacterial enzyme called β-lactamase
2. Alteration of target site (altering PBPs)
3. Decreased penetration to target site (thick outer cell membrane)

Question 11

Pharmacokinetics/dynamics of β-lactam abx

Answer 11

short half-life, excreted by kidneys, excellent tissue distribution
β-lactam abx have their rate of killing maximized at a low multiple of the MIC (time dependent killing)

Question 12

β-lactam abx operate best at above or below their MIC?

Answer 12

Above, you accomplish effectiveness by lower, yet more frequent dosing

Question 13

β-lactam allergic reactions: immediate (w/in an hour)

Answer 13

IgE mediated, erythema/pruritis, angioedema, urticaria/wheezing, and ANAPHYLAXIS AKA THE WORST

Question 14

β-lactam allergic reactions: late (>72 hours)

Answer 14

More common than immediate rxn. Rash, immune mediated destruction of WBC’s, RBC’s, Platelets, and SERUM SICKNESS (fever, rash, arthritis, glomerulonephritis)

Question 15

β-lactam adverse effects

Answer 15

Type 1 IgE mediated reactions, serum sickness (late), dermatologic, neurologic, diarrhea, hepatitis, renal, hematologic

Question 16

5 Spectrum Levels of the Penicillins

Answer 16

1. Narrow Spectrum
2. Antistaphylococcal, Penicillinase-resistant, narrow spectrum
3. Intermediate spectrum
4. Intermediate spectrum + β-lactamase inhibitors
5. Broad spectrum + β-lactamase inhibitors

Question 17

1st Spectrum: Narrow Spectrum abx is?

Answer 17

Penicillin

Question 18

1st Spectrum: Narrow Spectrum abx features

Answer 18

cheap, favorable therapeutic index, excellent tissue penetration.

Question 19

1st Spectrum: Narrow Spectrum abx works on which kinds of bacteria? (4)

Answer 19

1. Gram + cocci: GAS, GBS, Enterococcus
2. Gram - diplococci: Neisseria meningitidis
3. Spirochetes
4. Oral anaerobes

Question 20

1st Spectrum: Narrow Spectrum: You can treat staph aureus with penicillin? T/F

Answer 20

FALSE, you would NEVER because the resistance is so high in staph aureus. (also not in gonorrhea and strep pneumonia)

Question 21

1st Spectrum: Narrow Spectrum: Penicillin is prescribed clinically for 3 things

Answer 21

1. Pharyngitis (GAS)
2. Syphilis
3. Dental infection

Question 22

2nd Spectrum: Antistaphylococcal, Penicillinase-resistant, narrow spectrum: Abx? (2)

Answer 22

Oxacillin (or Nafcillin)

Dicloxacillin = oral form

Question 23

2nd Spectrum: Antistaphylococcal, Penicillinase-resistant, narrow spectrum: Oxacillin is mainly used against what bacteria?

Answer 23

Staphylococcus Aureus (that’s not MRSA). Some against streptococci

Question 24

2nd Spectrum: Antistaphylococcal, Penicillinase-resistant, narrow spectrum: Oxacillin doesn’t have activity against what?

Answer 24

Enterococci, gram - aerobes,