An antimicrobial composition containing a cationic polymer having limited antimicrobial activity (such as a hydrophobically-modified quaternary ammonium cellulose ether) and an antimicrobial compound (such as one or more compounds selected from the group consisting of diiodomethyl-para-tolylsulfone, ortho-phenylphenol, sodium pyrithione, zinc pyrithione, 3-iodo-2-propynylbutylcarbamate, 2-methyl-4-isothiazolin-3-one, 1,2-benzisothiazolin-3-one, 2-n-octyl-4-isothiazolin-3-one, 1-(3-chloroallyl)-3,5,7-triaza-1-azoniaadamantane chloride, 2-(4-thiazolyl)-benzimidazole, beta-bromo-beta-nitrostyrene, 2,4,4'-trichloro-2-hydroxyphenyl ether, chloroxylenol, chlorocresol, para-tert-amylphenol, N-(4-chlorophenyl)-N'-(3,4 dichlorophenyl)-urea, and para-hydroxybenzoic acid esters). The growth of microorganisms (such as Pseudomonas aeruginosa) can be inhibited by exposing the microorganism to such a composition.
