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Antimicrobial soaps - (Dec/17/2013 )

Regulated under a "tentative final monograph" from well back in the last century, the benefits and safety concerns for this category are driven largely by in vitro data of questionable application to the real world where pivotal epidemologic data would be almost impossible to generate.

-Phil Geis-

FDA challenge:

and the industry response:

-Phil Geis-

I've always wondered about the efficacy of these soaps - they are advertised as having >95% bacteriocidal activity, but given that they aren't used in surgery rooms (they have their own special soaps and disinfectants for that), I knew the advertising must be wrong misleading to say the least. 


I also wondered about the resistance side of things, but thought as they were using essentially a protein precipitation method, that there wouldn't be much potential for that to happen (little did I know).


It's real interesting, Bob.  There are in vitro reports that triclosan-induced antibiotic resistance in the lab but ironically Levy's own in-use study reports found none was induced in real life.  The report did not find a benefit.  Industry cites the following report that claimed antimicrobial soap to block transmission of pathogens via food -

Similarly, the endocrine-disruptor/estrogenic effect data are based on in vitro studies usually with isolated cells of various types.  


Industry cites the following report that claimed antimicrobial soap to block transmission of pathogens via food -


The same question of efficacy has been debated for close to 50 years and the Agency has allowed marketing all those years  under the same "tentative final monograph."

-Phil Geis-

Huh, interesting.  I wonder how much greater the "blockage of transmission by food" is c.f. normal soap and proper hand washing technique for normal levels of contamination.  I suspect that there wouldn't be much difference.


Look at the 2nd article, Bob.  The protocol had hands contaminated with Shigella flexneri or E. coli, washing hands with soap or antimicrobial soap, then handling inoculated melon ball.  Recovery from hands following washing and melon balls reportedly found significant difference between soap and antimicrobial soap. 


I've not looked at the paper for a couple of years - but assume it used lab strains that may or may not be representative of such microbes one might encounter in a real life situation.  Assume the soap was an authentic alkaline soap rather than detergent.

-Phil Geis-