Methicillin

Definition

Methicillin is a beta-lactam antibiotic used to treat bacterial infections caused by susceptible Gram-positive bacteria. It is most notable for its role in the development of methicillin-resistant Staphylococcus aureus (MRSA).

5 Must Know Facts For Your Next Test

1. Methicillin was introduced in the 1960s to counteract penicillinase-producing Staphylococcus aureus.
2. MRSA stands for methicillin-resistant Staphylococcus aureus, a significant cause of hospital-acquired infections.
3. Methicillin works by inhibiting cell wall synthesis in bacteria through binding to penicillin-binding proteins (PBPs).
4. Due to widespread resistance, methicillin is no longer used clinically and has been replaced by other antibiotics like oxacillin.
5. The mecA gene is responsible for methicillin resistance in MRSA, encoding an altered PBP that does not bind well to beta-lactams.

Review Questions

• What mechanism allows methicillin to inhibit bacterial growth?
• Why is methicillin no longer commonly used in clinical practice?
• What genetic element confers resistance to methicillin in MRSA?

Related terms

Penicillin: A group of antibiotics that were among the first medications effective against many bacterial infections.

Beta-Lactam Antibiotics: A class of broad-spectrum antibiotics containing a beta-lactam ring, including penicillins and cephalosporins.

Oxacillin: A beta-lactam antibiotic used as a replacement for methicillin in treating staphylococcal infections.