Bacitracin is a mixture of related cyclic polypeptides produced by organisms of the licheniformis group of Bacillus subtilis var Tracy. As a toxic and difficult-to-use antibiotic, bacitracin doesn't work well orally. However, it is very effective topically.

Mechanism of action

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Bacitracin interferes with the dephosphorylation of the C₅₅-isoprenyl pyrophosphate, a molecule which carries the building blocks of the peptidoglycan bacterial cell wall outside of the inner membrane ^*.

Clinical use

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As bacitracin zinc salt, and in combination with other topical antibiotics (usually polymyxin B and neomycin), it is used in ointment form for topical treatment of a variety of localized skin and eye infections, as well as for the prevention of wound infections. This ointment is sold in the United States under the brand name Neosporin.

In infants, it is sometimes administered intramuscularly for the treatment of pneumonias. This formulation is sold under the brand name Baciim®.

Polypeptide antibiotics

Bacitracin