Abstract
New derivatives of chitosan were synthesized by modification of chitosan (CTS) either with chloroacetyl chloride or with bromoacetyl chloride. The haloacetylated chitosan derivatives were quaternized by reaction with triethyl amine and triphenyl phosphine. The quaternized new derivatives of chitosan were tested against Gram-negative bacteria the Gram-positive bacteria Staphylococcus aureus, and the fungi by the cut plug method and viable cell counting methods. The results showed that the new chitosan derivatives have stronger antimicrobial activities than the chitosan itself. The examination of the treated cells by TEM showed complete discharge of cellular cytoplasm which led to the death of the cells.