Neomycin/Bacitracin

Neomycin is an aminoglycoside antibiotic from Streptomyces fradiae (C₂₃H₄₆N₆O₁₃x3 H₂SO₄, MW 908.88). Mixture derived from approx. 90 % Neomycin B (Framycetin) and approx. 10 % Neomycin C. Neomycin is active against Gram-positive and Gram-negative bacteria.
mechanism: Inhibits protein biosynthesis, inhibits phospholipase C and D

Bacitracin is a polypeptide antibiotic from Bacillus licheniformis (C₆₆H₁₀₃N₁₇O₁₆S; MW 1422.72). Mixture of 9 chemically similar components of the bacitracins, Bacitracin A is the main component. It is active mainly on Gram-positive bacteria, but also on Mycoplasma and Neisseria.
mechanism: Inhibits cell wall synthesis of Gram-positive bacteria by binding to bactoprenyl pyrophosphate.