Science Buddies: "Ask an Expert"

Which one is a more effective disinfectant - Benzalkonium chloride OR isopropyl alcohol?

What is the reason?

And lastly, is there any literature / articles to explain why which one is more effective than the other?

Thanks a lot

I looked around a bit and found several discussions about the pros and cons of each. Surpisingly, Wikipedia had a nice summary

Laboratory studies have shown lingering benzalkonium chloride may be associated with antibiotic resistance in MRSA[39][40] while no mechanism for resistance to alcohol has ever been described in bacteria.[41] Where alcohol sanitizers utilize 62%, or higher, alcohol by weight, only .1 to .13% of benzalkonium chloride by weight provides equivalent antimicrobial effectiveness.

Wikipedia by itself hardly stands as a legitimate source, but it's easy enough to look at the references and go back to the original material. Basically though, bacteria can become resistant to benzalkonium chloride but not to alcohol. Some studies suggest that the toxicity and side effects of benzalkonium chloride make it a poor choice. The drawbacks to alcohol include drying the skin and that some people will drink it.

You might find http://www.cdc.gov/hicpac/Disinfection_ ... de.html#a2 and http://www.cdc.gov/hicpac/Disinfection_ ... on.html#a1 interesting, and pop " Benzalkonium chloride compared to isopropyl alcohol" into a search engine and you'll find all sorts of discussions on the topic.

Howard