Antibacterial additive commonly used in consumer products such as deodorant soaps and "antibacterial" cleaners — the ingredients list on any bar of antibacterial soap will probably include triclosan. It works by inhibiting an enzyme, called FabI, needed for fatty acid synthesis and bacterial survival. Triclosan has been touted as a non-specific agent that attacks bacterial membranes and kills randomly, therefore not encouraging resistant strains.

In July of 2000 a research team at St. Jude Children's Research Hospital discovered that Streptococcus pneumonia has an alternative enzyme called FabK, which is unaffected by triclosan. Also, escherichia coli has demonstrated mutations in FabI which also can cause triclosan resistance. With widespread use of triclosan, resistant strains of this nature can be expected to become more common.

Since antibacterial soap is considered no more effective than regular hand soap in normal cleansing, there is some call for regulating the use of triclosan.

Purell and Ivory soap are considered good hand sanitizers, and do not contain triclosan.

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