Side-by-Side Comparison · 2026

Bacitracin vs Colistin

Bacitracin vs Colistin — mechanism, half-life, dosing, and research status compared. Which is right for your protocol?

Bacitracin
Antimicrobial Peptide

Bacitracin is a polycyclic peptide antibiotic from Bacillus subtilis licheniformis, first isolated in 1945 from wound cultures of a 7-year-old girl named Margaret Tracy (hence "bacitracin"). It is available OTC in Neosporin and similar triple-antibiotic ointments and is one of th...

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Colistin
Antimicrobial Peptide

Colistin (polymyxin E) is a cyclic lipopeptide antibiotic structurally related to polymyxin B, differing in the fatty acid chain and one amino acid residue. Like polymyxin B, colistin targets LPS and disrupts outer membranes of Gram-negative bacteria....

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Key Parameters
Parameter Bacitracin Colistin
Category Antimicrobial Peptide Antimicrobial Peptide
Research FDA Approved (topical) FDA Approved
Half-Life Hours (topical) Colistimethate (prodrug): 2-3 hours; active colistin: 14 hours
Typical Dose 400-500 units/g ointment 2.5-5 mg/kg/day CBA IV
Frequency 1-3x daily Every 8-12 hours
Route Topical IV (colistimethate) / Inhaled / Topical
FDA Status Approved (topical) Approved (systemic Gram-negative infections)

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Frequently Asked Questions
What is the difference between Bacitracin and Colistin?
Bacitracin: Bacitracin is a polycyclic peptide antibiotic from Bacillus subtilis licheniformis, first isolated in 1945 from wound cultures of a 7-year-old girl named Margaret Tracy (hence "bacitracin"). It is ava... Colistin: Colistin (polymyxin E) is a cyclic lipopeptide antibiotic structurally related to polymyxin B, differing in the fatty acid chain and one amino acid residue. Like polymyxin B, colistin targets LPS and ...
Which has a longer half-life, Bacitracin or Colistin?
Bacitracin half-life: Hours (topical). Colistin half-life: Colistimethate (prodrug): 2-3 hours; active colistin: 14 hours.
Can you stack Bacitracin and Colistin?
Bacitracin and Colistin are in the same category and used together in research protocols. Always consult relevant literature and follow appropriate guidelines.

For research use only. Not medical advice. ASCEND does not conduct or endorse any specific research protocol. Always consult relevant scientific literature and regulatory guidelines.