Enhanced antimicrobial activity of amphiphilic cationic polymers against a broad range of bacterial strains and skin microbes

Antimicrobial activity of n-butyl-substituted linear polyethylenimine (LB) polymers is investigated against a broad range of bacterial strains and skin microbes of acne lesions. Variation in the degree of alkylation significantly altered the activity of the modified polymers. Interaction of these polymers with the bacterial cell membrane resulted in the considerable changes in the surface morphology as visualized under electron microscopy, which confirmed the membrane-disruptive mode of action of these polymers. The projected polymers efficiently inhibited the proliferation of Gram-positive and Gram-negative bacteria. Hemolysis assay also demonstrated non-toxic nature of the modified polymers. On skin pathogens, MIC of all the formulations (130–300 μg/ml) was much lower than that of the standard antibiotics (400–1200 μg/ml). These studies demonstrated that the projected materials exhibited significantly higher antimicrobial activity against all the tested pathogens (bacterial strains and skin microbes) suggesting they could be developed as an improved class of antibacterials.