Bacitracin

• mixture of polypeptides

• used topically

Mechanism of action

• inhibits cell wall synthesis

• interferes with dephosphorylation and cycling of lipid through cytoplasmic membrane to cell wall

Activity

• gram-positive

  • esp Staphylococcus 

    • Staphylococcus aureus

    • Staphylococcus epidermidis

  • Group A streptococcus

Resistant

• Gram negative

  • through failure to penetrate cell wall