Chlorhexidine: antibacterial action and bacterial resistance.

Chlorhexidine is a clinically important antiseptic, disinfectant and preservative. It is a potent membrane-active agent against bacteria and inhibits outgrowth, but not germination, of bacterial spores, although it is not sporicidal. It shows high activity against wild-type and outer membrane mutants of Escherichia coli but some gram-negative bacteria are resistant to chlorhexidine by mechanisms not yet fully understood, although they appear to involve the outer, rather than the inner, membrane.