POLYMYXIN B, which is produced by Bacillus polymyxa (Bacillus aerosporus Greer), is a stable polypeptide with marked bactericidal action against many Gram-negative bacilli and especially against Pseudomonas aeruginosa. Variants of polymyxin were announced independently by three groups of investigators: Ainsworth, Brown, and Brownlee;1 Benedict and Langlykke,2 and Stansly, Shepherd, and White.3 These variants, designated A, B, C, D, and E, have similar antibacterial spectra but differ in their amino-acid components and toxicity.
The alteration of the bacterial flora by the widespread use of antimicrobial agents has increased the incidence of Proteus, Pseudomonas aeruginosa (Bacillus pyocyaneus), and Candida albicans as secondary invaders, owing to the elimination of sensitive bacteria and multiplication of these resistant species. This observation is true for the skin as well as for other locations. Owing to the high bactericidal activity of polymyxin B against Gram-negative organisms, conjunctivitis, granulating wounds, and burns infected