Bacitracin
Also known as: Bacitracin A
Bacitracin is a mixture of cyclic peptide antibiotics used mainly on the skin. Its topical and eye-product roles are distinct from the injectable form withdrawn in the United States because of serious kidney toxicity.
Quick Facts
A mixture of peptide antibiotics
Bacitracin contains closely related cyclic polypeptides made by bacteria in the Bacillus subtilis group; bacitracin A is its most active principal component. US topical ointments are available over the counter, either alone or combined with other antibiotics for minor wound care.
Supporting references: cyclic polypeptides; Bacillus subtilis.
Discovery and the origin of the name
Researchers isolated the antibiotic-producing strain in 1945 from a wound in seven-year-old Margaret Tracy. Its name combines Bacillus with Tracy. It emerged soon after penicillin in the early antibiotic era. Toxicity limited systemic injection, while topical use remained established.
Bacterial cell-wall inhibition
Bacitracin blocks recycling of C55, or undecaprenyl pyrophosphate, the lipid carrier that transports bacterial cell-wall building blocks. Binding prevents the carrier’s dephosphorylation and reuse, interrupting wall construction. Activity is strongest against gram-positive organisms such as staphylococci and streptococci. Poor skin absorption supports surface use; oral administration is not a way to treat body-wide infection.
Status depends on formulation
| Form | Status | Context |
|---|---|---|
| Topical ointment | Over-the-counter drug | Prevention of infection in minor cuts, scrapes and burns |
| Ophthalmic ointment | Prescription | Specific prescription eye preparations |
| Injection | Approval withdrawn in 2020 | Serious kidney-damage risk; no longer marketed in the United States |
Minor wounds and the petrolatum comparison
Bacitracin is a common first-aid ointment ingredient and is often paired with neomycin and polymyxin B in triple-antibiotic products. It is not clearly superior to plain petroleum jelly for clean minor wounds. In a randomized study of 922 dermatologic-surgery patients, infection rates were low and comparable with white petrolatum and bacitracin, while allergic contact dermatitis occurred only in the bacitracin group. This finding helps explain the preference of many clinicians for petrolatum in routine clean-wound care.
Supporting references: neomycin and polymyxin B; randomized trial.
Allergy and the withdrawn injection risk
Allergic contact dermatitis is a recognized risk, producing an itchy, red and sometimes blistering application-site rash. The American Contact Dermatitis Society named bacitracin its 2003 Allergen of the Year. Rare anaphylaxis has occurred even with topical use. Serious nephrotoxicity is associated with injection and drove withdrawal of that US form. On small skin areas, topical use is otherwise generally tolerated, with the allergy risk still relevant.
Supporting references: 2003.
Sources: [5]
References and further reading
This reference draws on Superpower’s Peptide Library and the research linked below. Peptide Dossier’s editorial team adapted and integrated the material on .
- go.drugbank.comA mixture of peptide antibioticsCited in: A mixture of peptide antibiotics
- statpearls.comA mixture of peptide antibioticsCited in: A mixture of peptide antibiotics
- reference.medscape.comMinor wounds and the petrolatum comparisonCited in: Minor wounds and the petrolatum comparison
- pubmed.ncbi.nlm.nih.govMinor wounds and the petrolatum comparisonCited in: Minor wounds and the petrolatum comparison
- pharmacytimes.comAllergy and the withdrawn injection riskCited in: Allergy and the withdrawn injection risk
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Disclaimer: This article is for informational and educational purposes only. It is not intended as medical advice. The information presented is based on published research and should not be used as a substitute for professional medical guidance. Always consult a qualified healthcare provider before starting any peptide protocol. Some peptides discussed may not be approved for human use by the FDA or equivalent regulatory bodies.