Wool can be an appropriate medium for growing and transferring microorganisms under favorable temperature and humidity conditions. These microorganisms can result in wool damage, skin irritation, or infections. A new and effective quaternary ammonium surfactant, N-dodecyl-N, N-dimethyl glycine cysteamine hydrochloride (DABM), has recently been synthesized. DABM can react with wool by means of its thiol group, either with cysteine-S-sulphonate residues (Bunte salts) of sodium bisulphite pretreated wool or with the disulfide bond of cystine wool, forming an asymmetrical disulfide bond. The antimicrobial activity of bisulphite-pretreated and untreated wool, both treated with DABM, is studied against gram-positive and gram-negative bacteria by means of the protective antibacterial AATCC, test method 100-1989 and SEM observation. Both wool samples show biocide activity against B. pumilus and bacteriostatic activity against S. aureus. The absence of gram-positive and gram-negative bacteria attached to the wool surface fibers is observed by SEM.