penicillins

Question 1

Natural Penicillins

Answer 1

Aqueous Penicillin G
Benzathine Penicillin
Procaine Penicillin G
Penicillin VK

Question 2

Penicillinase-Resistant Penicillins

Answer 2

Nafcillin
Oxacillin
Methicillin
Dicloxacillin

Question 3

Aminopenicillins

Answer 3

Ampicillin
Amoxicillin

Question 4

Carboxypenicillins

Answer 4

Ticarcillin

Question 5

Ureidopenicillins

Answer 5

Piperacillin

Question 6

B-Lactamase Inhibitor Combinations

Answer 6

Ampicillin-Sulbactam (Unasyn)
Amoxicillin-Clavulanate (Augmentin)
Ticarcillin-Clavulanate (Timentin)
Piperacillin-Tazobactam (Zosyn)

Question 7

Mechanism of action of B-Lactam Antibiotics

Answer 7

Inhibitors of cell wall synthesis

Question 8

Mechanisms of Resistance of B-Lactam Antibiotics

Answer 8

Destruction of B-lactamase enzymes

Alteration in PBPs

Decreased permeability of outer cell membrane in Gram(-) bacteria

Question 9

Pharmacodynamic Properties fo B-Lactams

Answer 9

Display time-dependent (T>MIC) bactericidal activity

Question 10

Bacterial Exception to Pharmacodynamic Properties of B-Lactams

Answer 10

Enterococcus spp.

Question 11

Elimination half-life of B-Lactams

Answer 11

<2 hours

Repeated, frequent dosing is needed for most B-Lactams to maintain serum concentrations above the MIC of the infecting bacteria for an adequate amount of time

Question 12

Exceptions to the short elimination half-life in B-Lactams

Answer 12

Ceftriaxone
Cefotetan
Cefixime
Ertapenem

Question 13

B-Lactam elimination route

Answer 13

Renal elimination
Primarily eliminated unchanged by glomerular filtration and tubular secretion

Question 14

Exemptions to renal elimination of B-Lactams

Answer 14

Nafcillin
Oxacillin
Ceftriaxone
Cefoperazone

Question 15

Cross-allergenicity of B-Lactam

Answer 15

All have risk of cross allergenicity

Question 16

Exception to cross-allergenicity in B-Lactams

Answer 16

All except aztreonam

Question 17

Classes of B-Lactams

Answer 17

Penicillins
Cephalosporins
Carbapenems
Monobactams

Question 18

Penicillins shared chemical structure

Answer 18

5-membered thiazolidine ring connected to a B-lactam ring

Question 19

What is different among the groups of penicillins and what does that do?

Answer 19

The side chains differ among the groups of penicillins

What it does:
Different antibacterial spectrums
Different pharmacokinetic properties
Greater B-lactamase stability

Question 20

MOA of Penicillins

Answer 20

Interfere with bacterial cell wall synthesis by binding and inhibiting enzymes (PBPs), which are located in the cell wall of bacteria and are primarily expressed during cell division

Question 21

PBPs that regulate the synthesis, assembly, and maintenance of peptidoglycan (cross-linking of the cell wall)

Answer 21

Transpeptidases
(cross-linking of the cell wall)
Carboxypeptidases
(breaks down proteins and peptides into smaller peptides)
Endopeptidases
(Break peptide bonds)

Question 22

Penicillins are bactericidal or bacteriostatic?

Answer 22

Bactericidal

Except against Enterococcus spp., where they are bacteriostatic

Question 23

Most common B-Lactamse resistance:

Answer 23

Production of B-lactamase enzymes

Question 24

Production of b-lactamase enzymes occurs in what Gram(+) aerobe?

Answer 24

Staphylococcus aureus

Question 25

Production of b-lactamase enzymes occurs in what Gram(-) aerobes?

Answer 25

H. influenzae N. gonorrhoeae M. catarrhalis K. pneumoniae E. coli Proteus spp. P. aeruginosa S. marcescens

Question 26

Production of b-lactamase enzymes occurs in what Gram(-) anaerobes?

Answer 26

Bacteroids fragilis

Question 27

Where do B-lactamase enzymes produced by Gram(-) bacteria reside giving it a very efficient mechanism of resistance?

Answer 27

Periplasmic space

Question 28

Examples of alteration in the structure of the PBPs leading to decreased binding affinity of the penicillins to the PBPs

Answer 28

Methicillin-resistant Staphylococcus aureus [MRSA] Penicillin-resistant Streptococcus pneumoniae [PRSP]

Question 29

Aside from b-lactamase resistance, what other method of resistance do Gram(-) bacteria utilize to decrease susceptibility to penicillins?

Answer 29

Altered porin proteins Inability of antibiotic to reach the PBP target due to poor penetration through the outer membrane of Gram-negative bacteria

Question 30

Natural Penicillin spectrum of activity against Gram(+) bacteria

Answer 30

Excellent against non-B-Lactamase-producing Gram(+) cocci and bacilli

Question 31

Aqueous penicillin G Benzathine Penicillin G Procaine Penicillin G Penicillin VK Gram (+) coverage

Answer 31

Group Streptococci (A, B, C, F, G) Viridans Streptococci *Some Streptococcus Pneumoniae (high level of resistance ~15-20%) Bacillus spp. Most Enterococcus spp. Corynebacterium spp.

Question 31

Aqueous penicillin G Benzathine Penicillin G Procaine Penicillin G Penicillin VK In regards to Staphylococcus spp.

Answer 31

Lack of susceptibility due to Penicillinase production (~5% susceptible)

Question 31

Aqueous penicillin G Benzathine Penicillin G Procaine Penicillin G Penicillin VK Gram (-) coverage

Answer 31

Primarily against some Gram(-) COCCI Neisseria meningitidis Non-B-lactamase-producing Neisseria gonorrhoeae Pasteurella multocida