Extra Antibiotics

Question 1

Bacitracin

Answer 1

MOA;
- binds to Bactoprenol Phosphate and inhibits the transportation of NAG & NAM across the cell membrane.

Spectrum;

• Gram +ve bacteria (s.aureus, s.epidermis, strep)
• only Topically! - skin and eye infections

Side effects = Severe Nephrotoxicicity

Question 2

Mupirocin

Answer 2

MOA;
- inhibits bacterial protein synthesis by selectively binding to isoleucyl-tRNA synthetase

Spectrum;

• gram +ve cocci (staph, MRSA, strep) *impetigo
• used Topically

Side effects;
- itching, redness, burning, contact dermatitis

Question 3

Fusidic acid

Answer 3

MOA;
- inhibitor of protein synthesis
- inhibits bacterial Elongation Factor G
= no translocation

Spectrum;

• gram +ve aerobes and anaerobes +MRSA
• skin infections and conjunctivitis

Side effects;
- Hepatotoxic

Question 4

Polymyxin E

Answer 4

MOA;
- bind Lipopolysacharides (LPS) of gram negative bacteria. They insert their hydrophobic tail into the membrane and disrupts the cell membrane

Spectrum;

• gram negative bacteria
• only topical treatment except for highly resistant pseudomonas & Acinetobacter

Side effects;

• Neurotoxicity (ataxia, dizziness, paraesthesia)
• Nephrotoxicity (acute tubular necrosis)

Question 5

Fosomycin

Answer 5

MOA;
- inhibits enolpyruvate transferase in bacteria
=blocking synthesis of NAG

Spectrum;
- gram positive and negative bacteria 
- Uncomplicated lower UTI
****Renal excretion unchanged ******
= urinary concentrate exceeds MIC 

Side effects;
- GI distress

Question 6

Nitrofurantoin

Answer 6

MOA;
- urinary antiseptic
- rapidly excreted into the urine
= suppress bacteriuria

Spectrum;

• Uncomplicated lower UTI
• **urine acidification enhances drug activity

Side effects; - with prolonged use & renal impaired

• GI distress, skin rash
• Pulmonary infiltrate
• Phototoxicity
• Acute hemolysis in G6PD