Page 92 - MNU-PM502- Pharmaeutical Microbiology Theoritical Book

Pharm D- Clinical Pharmacy Program Third Level Pharmaceutical Microbiology& Antimicrobials (PM 502)

2- Anti-staphylococcal penicillins
➢ Semisyntheyic

➢ Have bulky side chains that prevent their inactivation by the staphylococcal
B-lactamases. (Penicillinase-resistant penicillins)
➢ These penicillins are useful in treating infections caused by Staphylococcus

aureus (MSSA) and Staphylococcus epidermidis.
➢ This group of antibiotics includes
• Methicillin

• Oxacillin, Anti-staphylococcal penicillins
• Cloxacillin Not active against MRSA
• dicloxacillin. (methicillin resistant Staphylococcus aureus)
• Nafcillin

Methicillin - poor oral bioavailability, only parenteral

- treat infections caused by susceptible Gram-positive
bacteria, Methicillin sensitive Staphylococcus aureus
(MSSA)
no longer marketed due to renal toxicity, resistance

Oxacillin - Good oral availability
- More stable than methicillin

- Replaced methicillin
Dicloxacillin - Acid resistant

Spectrum
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