Bacterial Cell Wall and Folic Acid Agents

Question 1

Sulfonamides
- MOA

Answer 1

Bacteriostatic

Structural Analogs of PABA
- Inhibits Dihydropteroate Synthase (DHPS)
–> Preventing Folic Acid Synthesis

No Folic Acid = No purine/pyrimidine = No DNA/RNA

Question 2

Sulfonamides
- Adverse Effects

Answer 2

• Hepatitis
• Hypersensitivity (Stevens-Johnson Syndrome)
• Bone Marrow Depression
• Acute Renal Failure
• Cyanosis

Question 3

Folic Acid Antagonists
- MOA

Answer 3

Bacteriostatic

Folate Antagonists that resemble the Pteridine Ring of Folate
- Inhibt Bacterial Dihydrofolate Reductase (DHFR)

Combined with Sulfonamides to potentiate the decreased action on bacterial DNA/RNA synthesis

Question 4

Folic Acid Antagonists
- Adverse Effects

Answer 4

• Folate Deficiency
• Megaloblastic Anemia

Question 5

General Beta-Lactam Antibiotics
- MOA

Answer 5

Bactericidal

Selective and Irreversible Inhibitors of the Penicillin Binding Proteins (PBPs)
- Carboxypeptidases
- Transpeptidases
–> Prevents formation development of Peptidoglycan layer

Question 6

General Beta-Lactam Antibiotics
- Resistance

Answer 6

Bacteria produces enzymes like Beta-Lactamase that catalyze the hydrolysis of beta-lactam rings on antibiotics
- Inactivate beta lactam antibiotics before they reach PBPs

Function and Structure is similar to Transamidases

Question 7

Penicillin
- Pharmacokinetics

Answer 7

Majority of penicillin (90%) are eliminated through renal tubular secretions

Question 8

Penicillin
- Adverse Effects

Answer 8

• Hypersensitivity Reactions
• Anaphylactic Shock
• Proconvulsant Effect (If Penicillin G is given Intrathecally AKA through the spinal cord )

Question 9

Prototype Penicillin
- Characteristics

Answer 9

• Bactericidal
• Beta Lactamase Sensitive
• Poor Oral Availability
• Active against gram-positive

Question 10

Narrow Spectrum Penicillin
- Characteristics

Answer 10

• Bactericidal
• Beta Lactamase Resistant
• Poor/Good Oral Availability
• Active against gram-positive

Question 11

Broad Spectrum Penicillin
- Characteristics

Answer 11

• Bactericidal
• Beta Lactamase Sensitive
• Good Oral Availability
• Active against gram-positive/negative bacteria

Question 12

Extended Spectrum Penicillin
- Characteristics

Answer 12

• Bactericidal
• Beta Lactamase Sensitive
• Poor Oral Availability
• Active against gram-positive/negative bacteria
• Active against Pseudomonas aeruginosa, Klebsiella

Question 13

Beta Lactamase Inhibitors
- Characteristics

Answer 13

Combined with Amoxicillin

Question 14

Cephalosporins
- MOA

Answer 14

Bactericidal

Beta-Lactam Antibiotics from fungi
- Irreversible inhibition of PBPs

Question 15

Cephalosporin
- Classification

Answer 15

1st, 2nd, 3rd, 4th, 5h Generation

• Everything 3rd generation and on can cross into the brain

Higher Generation:
- More brain penetration
- Increased resistance to beta lactamases
- Spectrum to gram negative increases

Question 16

Cephalosporins
- Pharmacokinetics

Answer 16

Wide distribution in the body
- Some Second generation and Third Generation and higher can cross BBB

Question 17

Cephalosporins
- Adverse Effects

Answer 17

• Nephrotoxicity (Cefradine)
• Drug-Induced Alcohol Intolerance
• Bone Marrow Suppression
• Contraindicated in those who experience anaphylaxis in response to penicillin

Question 18

Carbapenems
- MOA

Answer 18

Bactericidal

Broad-Spectrum Beta Lactam Antibiotics
- Structural Difference from
penicillin / cephalosporin
–> Bind differently to PBPs

Maximizes Features of:
- Beta-Lactam Antibiotics
- Beta-Lactamase Inhibitors

Question 19

Carbapenems
- Pharmacokinetic

Answer 19

Imipenem is inactivated by renal dipeptidases
- Co-prescribed with Cilastatin

Question 20

Carbapenems
- Adverse Effects

Answer 20

Nephrotoxicity (Seizures with Imipenem)

Question 21

Monobactams
- MOA

Answer 21

Bactericidal

Specific to Gram Negative Microorganisms
- Irreversible Inhibitor of PBP3

Question 22

Glycopeptides & Lipopeptides
- Characteristics

Answer 22

• Last Resort treatment of Methicillin-Resistant Staphylococcus Aureus (MRSA)

Very Unstable
- Given by IV
- Given by mouth for Clostridium Difficile

Bacteria rarely develop resistance

Question 23

Glycopeptides & Lipopeptides
- MOA

Answer 23

Bactericidal

Bacterial Cell Wall Biosynthesis Inhibitors

1. Attaches to end of peptidoglycan precursor units D-ALA-D-ALA Terminus through 5 Hydrogen bonds
2. Inhibits transglycosylase and transpeptidase enzymes that cross link between NAM and NAG

Result:
- Interrupts Bacterial Cell Wall Synthesis

Question 24

Glycopeptides & Lipopeptides
- Resistance

Answer 24

Alteration of target causes resistance:
D-ALA-D-ALA
to
D-ALA-D-LAC

Enterococcus (VRE)
Staphylococcus aureus (VRSA)

Question 25

Glycopeptides & Lipopeptides
- Adverse Effects

Answer 25

Ototoxicity
Nephrotoxicity
Flushing (Redman Syndrome)
- Spike of histamine during rapid administration
Neutropenia (Low WBC)

Question 26

Polymyxin Antibiotics
- MOA

Answer 26

Bactericidal
Specific for Gram negative Bacilli (Pseudomonads)

1. Binds to phosphate group on cytoplasmic membrane
2. Displaces Calcium
3. Disrupts integrity of LPS
4. Bacteria dies

Question 27

Polymyxin Antibiotics
- Adverse Effects

Answer 27

Nephrotoxicity

Question 28

Fosfomycin
- MOA

Answer 28

Bactericidal
Broad Spectrum
Super Reactive

Inhibits Peptidoglycan synthesis
- Inactivates MurA Enzyme preventing peptidoglycan synthesis

• For UTI and Bladder Infection
• Meant to target multi resistant forms of E. Coli

Question 29

Fosfomycin
- Adverse Effects

Answer 29

Well tolerated