Methicillin sodium

Methicillin Sodium is a semi-synthetic penicillin derivative that was once widely used as an antibiotic to treat infections caused by Staphylococcus aureus bacteria, including methicillin-resistant Staphylococcus aureus (MRSA). It is no longer in clinical use due to the prevalence of resistance.

History

Methicillin Sodium was developed by Beecham Group in the United Kingdom in 1959, in response to the need for an antibiotic that could combat penicillin-resistant Staphylococcus aureus. It was the first of the beta-lactamase-resistant penicillins to be discovered.

Mechanism of Action

Methicillin Sodium works by inhibiting the final stage of bacterial cell wall synthesis, leading to cell death. It does this by binding to and inactivating penicillin-binding proteins (PBPs) on the inner surface of the bacterial cell membrane.

Resistance

Resistance to Methicillin Sodium is primarily due to the acquisition of a new PBP, known as PBP2a, which has a low affinity for beta-lactam antibiotics. This is encoded by the mecA gene, which is carried on a mobile genetic element called the staphylococcal cassette chromosome mec (SCCmec).

Side Effects

Common side effects of Methicillin Sodium include rash, nausea, vomiting, and diarrhea. Serious side effects can include anaphylaxis, kidney failure, and neutropenia.

See Also

• Penicillin
• Beta-lactamase
• Methicillin-resistant Staphylococcus aureus
• Antibiotic resistance