

What "hand sanitizer kills 99.99% of germs" really means. - zck
http://online.wsj.com/article/SB126092257189692937.html

======
fhars
What the article fails to mention is that the surviving 0.01% of a specific
microbe (or the ones on the 60th test plate) may just be the strains that are
resistant to the common antimicrobial agents in household cleaners, which will
then find themselves in an environment without much competition, allowing them
to thrive. So regular use of antimicrobial household cleaners allows you to
grow your very own unkillable strains of germs (and if you are really lucky
you may also get cross-resistancies against common antibiotics), putting you
and your household members at a considerably higher risk of severe infections.
It's all evolution 101.

Antimicrobial agents should be used sparingly and under strict medical control
(just like antibiotics, see the article on MRSA in Norway a few days ago),
household cleaning should be done with normal detergents or at most chlorine,
which has an unspecific toxic effect on microbes and does not lead to
resistancies.

~~~
timr
Eh...you're confusing antibiotic resistance with the fact that alcohol-based
sanitizers aren't 100% effective. There are two different things going on
here:

1) Most anti-microbials aren't antibiotics. They're compounds that happen to
kill bacteria by smacking them with the chemical equivalent of a sledgehammer,
preventing them from sticking to things, or some other, broad-spectrum
mechanism (i.e. they don't generally work by blocking an ion channel or
targeting a specific protein or pathway, as would an antibiotic).

2) Hand sanitizers are a special case of #1, where the vast majority are
simply alcohol-based gels. Effectiveness of these is determined by
concentration and time of exposure (the longer, the better), and in real life,
people don't leave them on long enough to be 100% effective.

For the most part, anti-microbial treatment is broad-spectrum, meaning there's
no single thing that an organism can do to escape damage. Membranes are
dissolved, cells are dessicated, proteins are denatured. Saying that a
bacterium could evolve resistance to this is a bit like saying that if you
dropped a car on a group of people, the survivors of the catastrophe would be
more fit to survive future car-droppings. It's hard for a bacterium to evolve
a protective mechanism against having its membrane proteins denatured, or
having all of its critical energetic pathways blocked. The damage is simply
too extensive.

~~~
Semiapies
Yes, if microbes are developing resistances to _ethyl alcohol_ , we've got
much bigger problems than truth-in-advertising. :)

------
jws
The article is a bit of a jumble. I've thought for some time that there should
be a "by line" reputation system for the internet in general so we can put
karma to print journalists.

I did enjoy the odd juxtaposition of AT&T's 97% wireless coverage number
presented as if somehow their deception is a commonly accepted fact.

------
celticjames
How effective is hand sanitizer compared to hand washing? Is hand sanitizer
more likely to be used than hand washing? Does the introduction of hand
sanitizer reduce infection more than hand washing? It's always more useful to
compare to a baseline or a standard practice.

------
RiderOfGiraffes
See also: <http://news.ycombinator.com/item?id=1018470>

------
philwelch
What's really depressing is the huge spike in hand sanitizer sales after H1N1.
Don't these people know that antibacterial agents do nothing against viruses?

~~~
prodigal_erik
Alcohol will damage the lipid membrane enveloping certain viruses (including
influenza) which helps them enter cells. I for one didn't know until now that
some viruses are unaffected because they don't have this.

