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Scientists Discover That Antimicrobial Wipes and Soaps May Be
Making You (and Society) Sick
By Rob Dunn | July 5, 2011
A few weeks ago as I was
walking out of a Harris
Teeter grocery store in
Raleigh, North Carolina, I
saw a man face a moment
of crisis. You could see it
in the acrobatic
contortions of his face.
He had pulled a cart out
of the area where carts
congregate, only to find
that its handle was sticky
with an unidentifiable
substance. He paused and
looked at the handle, as if to imagine the nature of the offense. Gum? Meat juice?
Chewed marshmallows? So many vulgar possibilities. Forlorn, he reached for an
antibiotic wipe conveniently placed by the door. He scrubbed his hands VERY diligently
and then pushed the cart back for someone else to rediscover [1].
Scenarios like this one
are playing out all over
America. There is an
epidemic of sticky, dirty
and otherwise gross
handles on shopping
carts. But it isn’t just
carts. Disgusting doorknobs have also been found, as have cryptically damp table-tops
in restaurants and even, sad as it is, slimy back rests on the weight machines in gyms!
Increasingly, the world seems to be rife with contamination. Fortunately, all of the main
companies producing hygiene products have offered a solution–sanitary, antibacterial,
antimicrobial, antibiotic, wipes, and soaps to kill anything that dares to creep into our
wholesome lives. These salves will cure us of the demons that dare to grow near us.
The really intriguing news–a kind of
breakthrough–is that the main
compounds in antibiotic wipes, creams
and soaps, triclosan and/or the
chemically similar triclocarban, have
also been sprinkled around our lives
more generally. A recent study notes
that triclosan is now used to
"impregnate surfaces and has been
added to chopping boards, refrigerators,
plastic lunchboxes, mattresses as well as
being used in industrial settings, such as
food processing plants where walls,
floors and exposed machinery have all
been treated with triclosan in order to reduce microbial load." You can now go home,
wipe your world down and live a happier life, surrounded by an antibiotic force field. Be
especially sure to wipe your children down. Children are just about the grimiest thing in
the world.
Yet, although I hesitate to digress or cause trouble, the devil on my shoulder, that voice
of so-called reason, is urging me to avail myself of more than the vague suspicion that
everything around me is contaminated. Maybe, the devil says, we should glance, just for
a second, at what scientists like to call–in their nasally ivory-tower voices–"the
evidence." I do not mean anything too fancy… Let’s just take a moment to look at a study
here and there that might be relevant as we go about coating our lives–from underpants
to kitchen pans–in antibiotic wonder.
For example, what if we just considered whether people who wipe down the world
around them with antibiotic soap or wipes are less likely to be sick. Of course, they must
be. The world is gross and they are, God bless them, clean, but let’s just check.
OK, we shouldn’t have checked. There are some problems. One is the actual evidence, or
just as often, lack thereof. Case in point: along with her colleagues, Allison Aiello, a
professor at the University of Michigan, recently surveyed all of the experimental or
quasi-experimental studies published in English between 1980 and 2006 on the
effectiveness of different hand washing strategies [2]. Aiello focused on studies that
compared different strategies, for example the use of normal soap versus the use of
antibiotic soap, in terms of their effect on the probability of developing gastrointestinal
or respiratory illness. Our intuition is that antibiotic soaps and wipes should make
everyone healthier. Aiello’s results were something else entirely.
Aiello’s first result was fine enough, but it set the stage for the trouble to come. She
found "the use of nonantibacterial soap with hand hygiene education interventions is
efficacious for preventing both gastrointestinal and respiratory illnesses." In other
words, if you wash your hands with soap (and are educated about washing your hands
with soap) you are less likely to get sick. Score one for intuition and grandma’s
admonitions. But then things went terribly wrong.
Aiello next considered the antibiotic soaps and wipes now used, in one form or another,
by 75% of American households. Odds are that you use them. Go check your labels.
Sadly, Aiello and colleagues found that antibiotic soaps and wipes with triclosan were no
more likely than good old-fashioned soap to prevent gastrointestinal or respiratory
illness. In Aiello’s words, "There was little evidence for an additional impact of new
products, such as alcohol-based hand sanitizers or antibacterial soaps compared with
nonantibacterial soaps, for reducing either gastrointestinal or respiratory infectious
illness symptoms."
For example, in a study
Aiello reviewed that was
conducted in Pakistan,
gastrointestinal illnesses
were reduced by half
when people washed
their hands with soap
and by a little less than
half when they washed
their hands with
antibiotic soap [3]. What
is worse, perhaps the
most comprehensive
study of the
effectiveness of antibiotic and non-antibiotic soaps in the U.S., led by Elaine Larson at
Columbia University (with Aiello as a coauthor), found that while for healthy hand
washers there was no difference between the effects of the two, for chronically sick
patients (those with asthma and diabetes, for example) antibiotic soaps were actually
associated with increases in the frequencies of fevers, runny noses and coughs [4]. In
other words, antibiotic soaps appeared to have made those patients sicker. Let me say
that again: Most people who use antibiotic soap are no healthier than those who use
normal soap. AND those individuals who are chronically sick and use antibiotic soap
appear to get SICKER.
Here, then, is the evidence we need, evidence very clearly at odds with our intuition to
scrub and scrub. Yet hardly anyone has followed up on Larson’s study and no one has
reexamined what happens with chronically sick patients and antibiotic soaps. The truth
is that few biologists are studying what antibiotic soaps do to us. Still, the evidence
indicates that when confronted with a dirty grocery store cart handle, we should just
wash with soap and water like our great grandmothers would have done (if they had had
grocery carts). At the very least, antibiotic wipes do not appear to help us and, it may be
that they are actually hurting us.
The devil on my shoulder suggests we need to take the radical step of actually thinking
for a second about what happens when you wash your hands, or whatever other part.
This is a step almost never taken in the study of illness. Our skin (just like Lady Gaga’s
skin) is covered in bacteria species. More than a hundred species of bacteria (not to
mention fungi and other kinds of organisms) can be found on a single hand of any given
adult [5] or for that matter belly button, forehead or other part, at any given moment
(Image of some of the more abundant bacteria in the author’s belly
button:http://www.wildlifeofyourbody.org/?page_id=8 ). It appears that those species
include two main groups. There are the "native" species, our own bodily citizens that
have evolved to live in peace on our skin and, in doing so, benefit us by acting as a kind
of defensive layer. Then there are the tourists. It is these tourists that cause us harm, the
tourists who bear chemical knives.
When you wash your hands, the goal is not to kill all the microbes. As Larson and a
group of colleagues put it in a 2003 paper "Handwashing with a non-antimicrobial soap
does little to modify the natural [citizen] flora. In fact, such an effect would be
undesirable." What is desirable is, instead, to kill the tourists who have just turned up
but not yet established, or at least the dangerous among those newly arrived species. Kill
the tourists is a reasonable hand washing motto (although the truth is we still know
surprisingly little about the citizens; they are the neglected serfs of our bodies). Soap is
thought to be effective at killing the tourists, not always, but at least often, although this
hypothesis has never been directly tested.
But what do antibiotic wipes and soaps do?
Amazingly, no one really knows. In the
vacuum of a laboratory they can kill both
viruses and bacteria, but what about on the
jungle of our bodies? It seems possible that
they are able, in some cases, to kill both
some of the tourists AND some of the
citizens. Perhaps (which is to say, I am
mostly guessing for the rest of this
paragraph) when we are mostly healthy,
this doesn’t matter; the bacteria regroup
and recover or our body in other ways
defends. But when we are already unwell, it
may be that this is enough to make us more
unwell by killing both natives and tourists and, in some cases, allowing the weediest
tourists to recolonize first. Maybe, but this is just my scientific intuition which, let’s be
honest, needs to be as carefully doubted and picked at as with our intuitions more
generally.
What we do know is that the influence of these wipes and salves does not end with our
hands, but instead spreads from them down our drains and out into society. What
happens when antibiotic soaps and suds go down drains? To find out, a group of
scientists recently made artificial drains clogged with bacteria (oh, the difficulties of
science) and then subjected them to low and high doses of triclosan (similar to what
happens when your detergent goes down the drain). Even at high concentrations,
triclosan appears to have no effect on the number of bacterial cells in our drains. BUT, it
does affect which species are found there. Triclosan kills "weak" bacteria but favors the
tolerant, among them species of bacteria that eat triclosan [6]. Yes, I said eat triclosan.
Triclosan may also favor lineages of bacteria that are also resistant to the oral antibiotics
used in hospitals and elsewhere [7], though how often and consistently is, as of yet,
unclear. Nonetheless, the hint of the tougher future triclosan might be favoring is,
perhaps, a bit troubling.
Nor are drains the end of the story. Triclosan continues its journey, the little chemical
that could, on to sewage treatment plants and into water supplies. In many municipal
water supplies triclosan can now be found in relatively high concentrations. Those high
concentrations affect the microbes that are always present in water, but also appear to
act as endocrine disrupters in fish. For example, fish exposed to triclosan have lower
sperm counts than those that are not [8]. Even if you don’t care about the sex lives of
fish, this might still worry you, given the great similarities, on evolutionary grounds,
between the hormones of fish and humans [9].
But I apologize. All of this was a diversion from the original story of the man with the
cart, the man wringing his hands. This story digressed from his story, just as the
consequences of his choice appear to cascade away from him out into the world.
The man continued on into the store, pausing only briefly to look at me, as if maybe he
knew me. Then I saw that he was looking at my son. I looked at my son too, which is
when I saw his marshmallow covered hands. I mouthed sorry back to the man, having
realized, of course, that it was my cart he had first taken. My son would have mouthed
sorry too, if he talked yet, and if his mouth wasn’t so gummed up with marshmallows.
"Sorry…," I was going to mouth again, but then he was gone and we needed to be going
too, to get home and eat, after washing our hands, but just with good old fashioned
soap. I’ll abandon the antimicrobial soap, detergent, and wipes. And I am pretty sure
that I have never purchased the other antimicrobial products, whether the counter tops
or underpants. This may seem sad, as though we have lost the war on the bad bacteria
and viruses, those tourists with their counterfeit visas. If it does, I extend my apologies
to you too. What is worse is that we seem to have lost it at a terrible time, what with all
of the gross shopping carts and, more seriously, the reality that last year 2 million
people died of respiratory infections. The good news, though, is that scientists have
figured out a way to reduce the frequency that people get sick by as much as forty
percent.
It turns out that although we know that washing our hands prevents a range of illnesses
and are incredibly eager to buy products marketed to kill germs, we don’t actually take
the simpler measure of washing hands in the first place. A study of nearly eight
thousand individuals in five U.S. cities found almost half of the participants failed to
wash their hands after going to the bathroom. In this light, no mystery salve is
necessary, no miracle cure, special wipe, or magic. We need to wash our hands, because
soap does the body good, at least in all the ways studied so far. It is not fancy. It is not
expensive or heavily marketed and yet it works, as it long has, even though as of yet, no
one can conclusively, unambiguously, tell you why.
———————————————————————————————————————
[1] Those who are ignorant of cart history are doomed to repeat it.
[2] Aiello AE, Coulborn RM, Perez V, Larson EL. 2008. Effect of hand hygiene on
infectious disease risk in the community setting: a meta-analysis. Am J Public
Health 98:1372-1381.
[3] Luby SP, Agboatwalla M, Painter J, Altaf A, Billhimer WL, Hoekstra RM. Effect of
intensive handwashing promotion on childhood diarrhea in high-risk communities in
Pakistan: a randomized controlled trial. JAMA. 2004;291:2547–2554.
[4] Larson EL, Lin SX, Gomez-Pichardo C, Della-Latta P. Effect of antibacterial home
cleaning and handwashing products on infectious disease symptoms: a randomized,
double-blind trial. Ann Intern Med. 2004;140:321–329.
[5] Fierer, N. M. Hamady, C.L. Lauber, R. Knight. 2008. The influence of sex,
handedness, and washing on the diversity of hand surface bacteria. Proc. Natl. Acad.
Sci, USA. 105: 17994-17999.
[6] McBain, A. J.; Bartolo, R. G.; Catrenich, C. E.; Charbonneau, D.; Ledder, R. G.; Price,
B. B.; Gilbert, P. Exposure of sink drain microcosms to triclosan: Population dynamics
and antimicrobial susceptibility. Appl. Environ. Microbiol. 2003, 69, 5433−5442.
[7] Aiello AE, Larson EL. Antibacterial cleaning and hygiene products as an emerging
risk factor for antibiotic resistance in the community. Lancet Infect Dis. 2003;3:501–
506.
[8] Raut, S. A., and R. A. Angus 2010. Triclosan has endocrine-disrupting effects in male
western mosquitofish, Gambusia affinis. Environ Toxicol Chem 29: 1287–1291.
[9] Rees Clayton, E.M., Todd, M., Dowd, J.B., Aiello, A.E.† (2010) The impact of
bisphenol A and triclosan on immune parameters in the US population, NHANES 20032006. Environmental Health Perspectives
*
About the Author: Rob Dunn is a science writer and biologist in the Department of Biology at
North Carolina State University. His first book, Every Living Thing, told the stories of the
sometimes obsessive, occasionally mad, and always determined, biologists who have sought to
discover the limits of the living world. His new book, The Wild Life of Our Bodies, explores how
changes in our interactions with other species, be they the bacteria on our skin, forehead mites
or tigers, have affected our health and well being. Rob lives in Raleigh, North Carolina with his
wife, two children, and lots of microbes.