Lecture Notes on Bacitracin

Introduction to Bacitracin

• Type: Peptide antibiotic (short protein chains).
• Origin of Name: Isolated from Bacillus subtilis, initially found in a wound from a patient named Tracy.

Mechanism of Action

• Function: Blocks the production of the bacterial cell wall.
• Specific Action:
  • Does not interfere directly with cell wall production.
  • Inhibits the movement of peptidoglycan precursors from inside the cell to the cell wall.
  • Prevents the cell wall from being strong enough to protect against osmotic pressure, leading to bacterial death.

Spectrum of Activity

• Broad-spectrum: Effective against both gram-positive and gram-negative bacteria.

Primary Uses

• Main Targets: Gram-positive skin organisms such as Staphylococcus and Streptococcus.
• Administration:
  • Can be used orally or intramuscularly, but rarely due to nephrotoxicity (kidney damage).
  • Primarily used topically.

Combination Therapy

• Triple Antibiotic Ointment:
  • Combined with polymyxin B and neomycin.
  • Known as the "triple antibiotic" or by the brand name Neosporin.

Conclusion

• Usage: Mainly topical due to potential kidney damage if used systemically.
• Bacitracin is an essential component in treating skin infections effectively when combined in topical formulations like Neosporin.