Saturday, September 19, 2015

Are Antimicrobial Soaps Effective?

Do antibacterial soaps protect you against dangerous bacteria? The answer is probably not.

In a study published in the Journal of Antimicrobial Chemotherapy, researchers examined the effectiveness antimicrobial liquid soaps containing triclosan, the most common ingredient in these soaps. First, they exposed 20 different strains of harmful bacteria to the soaps in petri dishes. The antimicrobial soaps did kill the bacteria, but only after 9 hours or more of exposure. Then, to test the effectiveness of the antimicrobial soaps under more real-world conditions, they spread bacteria on the hands of volunteers and asked them to wash their hands in cold water for 30 seconds with either antimicrobial or normal (non-antibacterial) soaps. Under these conditions, there was no difference between the antimicrobial soaps and the normal soaps in terms of their ability to kill the bacteria.

The bottom line is that antimicrobial soaps containing triclosan do have antimicrobial properties under certain conditions (9 hours!), but they are not effective under ordinary hand-washing conditions. It's something to think about, especially since any exposure to antimicrobial agents is likely to increase antibiotic resistance to that antimicrobial agent in the long run.

On a totally unrelated subject, it's a pet peeve of mine that the original article in the Journal of Antimicrobial Therapy is not available to the public for free; you can only see the abstract. If it's important information that was funded by public funds, it should be available to the public. In this particular case you can get more information from the popular press than from the journal itself. And that's a shame.

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