Antibiotics

Question 1

Beta-lactams

• Examples
• Mechanism
• Excretion

Answer 1

Includes

• Penicillin
• Cephalosporins

Inhibit peptidoglycan crosslinking

Mainly renally excreted

Question 2

Beta-lactamase inhibitors

• Mechanism
• Examples

Answer 2

Beta-lactamase enzymes are usually produced by gram negative/ anaerobic bacteria

Inhibitors stop beta lactam from being degraded by these bacteria

Examples (CAST)

• Clavulanic acid (Co-amoxiclav)
• Sulbactam (ampicillin)
• Tazobactam (piperacillin to make tazocin)

Question 3

Tazocin

• Mechanism
• Indications

Answer 3

Mechanisms

• Tazobactam combined with piperacillin
• Beta-lactamase inhibitor+ beta lactam

Indications
- Pseudomonas infections
(pneumonia, peritonitis)

Question 4

Aminopenicillin

• Examples
• Clinical use

Answer 4

Amoxicillin- PO/ IV
Ampicillin- IV/IM

Uses: some gram positive aerobes, gram - bacilli (HHEELPSS)
- H.pylori
- H. influenzae
- E. coli
- Enterococci
- Listeria
- Proteus
- Salmonella
- Spirochetes
-

Question 5

Piperacillin

• Mechanism
• Indications

Answer 5

Ueridopencillin
- Only given IV

Use- extended spectrum

• Gram negative bacilli
• Pseudomonas
• Anaerobes

Question 6

Glycopeptides

• Mechanism
• Examples
• Indications

Answer 6

Inhibits cell wall synthesis by inhibiting peptidoglycan
- different site to pencillin

Examples
- Vancomycin

Uses: broad spectrum gram positive

• MRSA
• S. epidermis
• Enterococci
• C. difficile

Question 7

Aminoglycosides

• Mechanism
• Examples
• Uses

Answer 7

Inhibits protein synthesis by binding to 30S subunit.

Examples

• Gentamicin
• Streptomycin

Uses

• Severe Gram - bacilli
• Streptomycin: MTB

Question 8

Tetracyclines

• Mechanism
• Examples
• Uses

Answer 8

Inhibits protein synthesis by blocking ribosome sites
- Different site to aminoglycosides

Examples

• Tetracycline
• Doxycycline
• Demeclocycline

Uses

• Atypical bacteria: mycoplasma, Chlamydia
• Acne

Question 9

Macrolides

• Mechanism
• Examples
• Uses

Answer 9

Inhibits protein synthesis by blocking translation in ribosome

Examples

• Erythromycin
• Azithromycin
• Clarithromycin

Clinical use

• Atypical pneumonia
• URTI
• Chlamydia STI
• Gram + cocci.
• Neisseria

Question 10

Cephalosporins

• Mechanism
• Examples
• Uses

Answer 10

Beta lactam
- Disrupt peptidoglycan synthesis

Examples

• Cefepime
• Ceftazidime
• Cefaclor
• Cephalexin (1st)

Uses

• First generation= Gram positive. Skin infections
• Later generations= gram negative activity