Bacitracin - Healing blisters on my feet since 1983

• antibiotic consisting of a mixture of similarly-structured cyclic polypeptides produced by a particular strain (Tracy-I) of Bacillus subtilis, a spore-forming soil bacterium
• it gets its name from the fact that this particular strain of bacterium was first isolated and cultured in the 1940s from damaged tissue and dirt removed from an open (compound) fracture sustained by a little girl named Margaret Tracy (Bacillus + Tracy = Bacitracin)
• the drug was subsequently discovered by Balbina A. Johnson (a bacteriologist) and Frank L. Meleney (a surgeon)
  
• broad spectrum of action (kills lots of different bacteria, especially Gram-positive ones)
• royally screws up bacterial cell wall formation by binding to and inactivating the lipid carrier required to transport cell wall components (peptidoglycan monomers), which are synthesized intracellularly, outside the bacterial cell membrane where the wall is formed
• hinders the synthesis of sterols (e.g. cholesterol) in mammalian cells, which most commonly manifests itself as nephrotoxicity (kidney toxicity) if administered systemically (e.g. intravenously) in people
• is now primarily used as a topical antibiotic (e.g. skin ointments like Polysporin that are specially formulated so as to prevent absorption of the drug beyond the site of application)
• often combined with other antibiotics like neomycin and/or polymyxins in order to increase potency and decrease the potential for the development of drug resistance
• can cause allergic contact dermatitis (ACD) and, rarely, anaphylactic shock (which can potentially kill you)
  

- Kalant H, Grant D, and Mitchell J. Principles of Medical Pharmacology 7th ed. Toronto: Saunders Canada, 2006.
- Jacob SE, James WD. From road rash to top allergen in a flash: bacitracin. Dermatol Surg. 2004 Apr;30(4 Pt 1):521-4.
- http://en.wikipedia.org/wiki/Bacitracin