Straight Dope Message Board

[ksweetman]

There are some who maintain that the recent rise in allergies is due to all this sanitary mania. Our immune systems have nothing to which to react, so they go haywire.


***********************
LINK TO COLUMN: http://www.straightdope.com/columns/...hand-sanitizer

[guizot]

Originally Posted by ksweetman

There are some who maintain that the recent rise in allergies is due to all this sanitary mania. Our immune systems have nothing to which to react, so they go haywire.

The anti-microbial soap products with triclosan have been shown to actually increase illnesses in households with susceptible inhabitants. The products with just alcohol--while maybe not effective for all that people think they are--seem to be okay. But if you're using it a lot, it might dry out your skin, and that can be problematic in other ways, I suppose.

[gazpacho]

I think that point 10 is wrong.

10. Chances are this product contains alcohol — generally 120 proof and up. It’s not, however, the kind of alcohol you’re supposed to drink. If you do anyway, and we know from the medical journals that some are tempted, be aware that chugging a 450-milliliter bottle is a ticket to the ICU.

Purell says it contains 62% Ethyl alcohol. That is the drinking kind.

[DSYoungEsq]

Helpful link to the column in question: How are you supposed to use hand sanitizer?

[Frank Saxon]

Over here (Netherlands), hand sanitizer was quite the rage during the hype of the mexican flu outbreak and subsequent end of the world.
A tv consumer program had some lab tests done that showed the working of hand sanitizer to be as good as water (not water and soap).

The problem is that the alcohol evaporates before it has a chance to kill all the germs. Since no rinsing is involved, our remaining guests simply continue to party.

[Winston Smith]

Originally Posted by gazpacho

I think that point 10 is wrong. Purell says it contains 62% Ethyl alcohol. That is the drinking kind.

Ethyl alcohol can still be denatured, which is what makes it undrinkable.

Cite: http://en.wikipedia.org/wiki/Denatured_alcohol

[jlellis]

In heart surgery we use a goopey hand sanitizer. It has prolonged antimicroial effect. Really.

[Irishman]

Just checked the hand sanitizer here at work.

In addition to 66% ethyl alcohol, it has aloe vera, carbomer, and triethanolamine.

Carbomer is an alternate name for acrylic acid, which is used as a thickener and emulsifier.

http://en.wikipedia.org/wiki/Acrylic_acid

Yum yum.

So whether or not the ethanol is denatured alcohol, the hand sanitizer mix is not the drinking kind.

I don't particularly care for the stuff, but I do note that it is flammable.

[debbiemoore]

There is one more important aspect of hand sanitizsers and that is their role in the evolution of resistant strains.

I totally agree with the comment that fear drives the market for these products, but I think some clarification on how this fear actually drives evolution of more resistant strains needs to be addressed, because as I see it, we are all slowly getting sucked into a downward spiral of paranoia which can only end badly for us humans.

Commensal populations on our skin are in some kind of balance and regular use of cosmetic sanitizers (as opposed to industrial strength, medical sanitizers) disrupts that balance - all the weak or useful bacteria get wiped out by these partially effective or badly used antibacterial gels/lotions and the tough guys get left behind. With the competition for resources wiped out, this kind of fast-tracked selection pressure means the tough guys very quickly take over and become the dominant strains. Any bacterial mutation that toughens up against antibacterial creams will proliferate and before you know what's happened, you get another strain of MRSA on your hands - literally...

You also need more than a couple of seconds to kill bacterial (which is usually the amount of time people give to their hand-washing), for example the bacteria causing tuberculosis needs a good 15 seconds being soaked in a 95% ethanol aqueous solution before it dies, and that's the industrial strength, anything weaker could need about a minute or so of soaking to be effective. And in any case, once the hands are aseptic the next thing anyone will do is touch the bathroom door handle to go back into the office, which replaces all the "bugs" you just killed...

Last I heard, no hand gels reach the EN1500 standard for bacterial removal. Since soap happily messes up bacterial membranes and makes them shrivel up and die, I would seriously stick to using soap - it costs less, smells better and is just as effective - as long as it is used properly!

[TSBG]

Originally Posted by debbiemoore

There is one more important aspect of hand sanitizsers and that is their role in the evolution of resistant strains.

I totally agree with the comment that fear drives the market for these products, but I think some clarification on how this fear actually drives evolution of more resistant strains needs to be addressed, because as I see it, we are all slowly getting sucked into a downward spiral of paranoia which can only end badly for us humans.

Commensal populations on our skin are in some kind of balance and regular use of cosmetic sanitizers (as opposed to industrial strength, medical sanitizers) disrupts that balance - all the weak or useful bacteria get wiped out by these partially effective or badly used antibacterial gels/lotions and the tough guys get left behind. With the competition for resources wiped out, this kind of fast-tracked selection pressure means the tough guys very quickly take over and become the dominant strains. Any bacterial mutation that toughens up against antibacterial creams will proliferate and before you know what's happened, you get another strain of MRSA on your hands - literally...

You also need more than a couple of seconds to kill bacterial (which is usually the amount of time people give to their hand-washing), for example the bacteria causing tuberculosis needs a good 15 seconds being soaked in a 95% ethanol aqueous solution before it dies, and that's the industrial strength, anything weaker could need about a minute or so of soaking to be effective. And in any case, once the hands are aseptic the next thing anyone will do is touch the bathroom door handle to go back into the office, which replaces all the "bugs" you just killed...

Last I heard, no hand gels reach the EN1500 standard for bacterial removal. Since soap happily messes up bacterial membranes and makes them shrivel up and die, I would seriously stick to using soap - it costs less, smells better and is just as effective - as long as it is used properly!

Wouldn't a thorough hand-washing also kill "beneficial" bacteria? And what's to prevent bacteria from evolving "soap resistance"?

[Bearcat69]

Excuse me if this is slightly off-topic, but I couldn't resist mentioning the latest in germaphobia: the no-touch soap dispenser. The advertising preys on the fear of germs residing on that nasty pump handle.

I wouldn't fear those germs if someone would only come up with a substance that could cleanse the germs from my hands. Oh right, there's the soap I just squirted and the water from the tap right there in the kitchen.

Nevermind, then.

[Cheshire Human]

Originally Posted by debbiemoore

... for example the bacteria causing tuberculosis needs a good 15 seconds being soaked in a 95% ethanol aqueous solution before it dies, and that's the industrial strength,...

Industrial strength???? Hell. That's good old-fashioned drinkable Everclear!

[Freudian Slit]

So how do you know the "right" amount of germs to be exposed to? Obviously too much exposure is bad but now apparently so is too little...

[rlsentell]

"Nosocomial"? Really? On the five-dollar-word scale, that ranks at about ten cents. OK, maybe twenty.

The five-dollar version is "iatrogenic". Sheesh.

[Mister Rik]

My sister (registered nurse) and I (professional cook) both dislike hand sanitizers for the same reason: they make the less-informed people think they don't need to wash their hands. Seriously, I once saw a waitress dip her hands in dirty dishwater, dry them off, then use hand sanitizer

Originally Posted by Bearcat69

Excuse me if this is slightly off-topic, but I couldn't resist mentioning the latest in germaphobia: the no-touch soap dispenser.

They installed one of those over the handwashing sink in my work kitchen. They installed it too high on the wall. When I bend down to rinse my hands it shoots me in the head.

Originally Posted by rlsentell

"Nosocomial"? Really? On the five-dollar-word scale, that ranks at about ten cents. OK, maybe twenty.

The five-dollar version is "iatrogenic". Sheesh.

I remember reading the warning label on some sort of industrial cleaning chemical some years ago, and was amused to see that "do not induce vomiting" was worded something like, "inducement of regurgitation is contraindicated".

[Jackmannii]

Overuse of hand sanitizer might just cause you to test positive for alcohol intake.

Really.

That study fortunately did not suggest that after a day's work in health care you could flunk the breathalyzer test if stopped by a patrol unit. Otherwise I'd be concerned (I tend to go through a fair amount of hand sanitizer during a day's work at the hospital).

If it comes down to resistant bugs arising through overuse of hand sanitizer/hand washing as opposed to what infections I might contract if food and health care workers don't keep their hands clean, I'd rather they overdo on the hand cleanliness.

And I think that there's still plenty of dirt and yuck out there to keep our immune systems revved up, even with rampant personal hygiene , vaccines and the like. All of your computer keyboards, for instance, if swabbed right now would probably culture out an incredible array of bacterial and fungal life forms.

[DB Cooper]

Singapore Changi airport has hand sanitiser stations all through the airport.

As this airport also had thermal cameras looking for high-temperature arrivals during the asian flu epidemic it's probably not surprising.

However as a lot of germs get transferred from hand to face - e.g. cold & 'flu - then ready availability of hand sanitisers in a mass transit area is probably a good idea,

[WarmNPrickly]

Originally Posted by debbiemoore

Commensal populations on our skin are in some kind of balance and regular use of cosmetic sanitizers (as opposed to industrial strength, medical sanitizers) disrupts that balance - all the weak or useful bacteria get wiped out by these partially effective or badly used antibacterial gels/lotions and the tough guys get left behind. With the competition for resources wiped out, this kind of fast-tracked selection pressure means the tough guys very quickly take over and become the dominant strains. Any bacterial mutation that toughens up against antibacterial creams will proliferate and before you know what's happened, you get another strain of MRSA on your hands - literally

I'd like to see some actual literature to back this up. While it is true that bacteria can develop resistance to some hostile environments, this logic looks too much like an unjustified extension of antibiotic resistance. It needs to be emphasized that antibiotic is not the same as antibacterial. I think it is highly unlikely that resistance to ethanol based hand sanitizers is going to translate to methicillin resistant staph infections. I think that the mechanisms that each operate to kill the bacteria are fundamentally different.

[Jackmannii]

Originally Posted by WarmNPrickly

While it is true that bacteria can develop resistance to some hostile environments, this logic looks too much like an unjustified extension of antibiotic resistance. It needs to be emphasized that antibiotic is not the same as antibacterial. I think it is highly unlikely that resistance to ethanol based hand sanitizers is going to translate to methicillin resistant staph infections. I think that the mechanisms that each operate to kill the bacteria are fundamentally different.

The medical literature backs this up. I have seen no evidence that bugs are mutating and developing resistance to nonspecific killing agents such as those in hand sanitizers. More information debunking sanitizer myths here (addresses the claim that immunity is compromised by too much hand cleansing) and here.

[Irishman]

Originally Posted by Bearcat69

Excuse me if this is slightly off-topic, but I couldn't resist mentioning the latest in germaphobia: the no-touch soap dispenser. The advertising preys on the fear of germs residing on that nasty pump handle.

Agreed. Hysteria.

Originally Posted by Jackmannii

If it comes down to resistant bugs arising through overuse of hand sanitizer/hand washing as opposed to what infections I might contract if food and health care workers don't keep their hands clean, I'd rather they overdo on the hand cleanliness.

But does that mean it is appropriate for everyone to use the same level of hygiene as health care workers and food preparers?

I'm stil interested in the difference in how the alcohol kills vs antibiotics and why it is not an issue. The links provided didn't really explain.

Also, that first one is poorly layed out. It looked at first like it was listing myths, but in fact was listing the statements that were truths as rebuttals to the claims.

[TSBG]

I might be paraphrasing badly, but I believe that triclosan disrupts only one site on the cell membrane in the course of killing the cell, thus is easy to adapt to, but alcohol disrupts many sites on the cell membrane and thus is harder to adapt to--though I suppose not impossible.

[WarmNPrickly]

Triclosan is not an antibiotic. It is an antibacterial. I am not certain that resistance to triclosan has been demonstrated outside the laboratory, and even if it did, that this resistance would translate to methicillin resistance.

I'm not a doctor, but methicillin resistance does not usually translate to tetracycline resistance which doesn't translate to vancomycin resistance. If the antibiotics don't cause cross resistance between classes, then how likely is it that something different enough to not be classified as an antibiotic, cause resistance to compounds even less related?

I do understand though, that MDR bacteria can be facilitated with ABC transport over expression. I think, in this way, resistance can be effective across classes of antibiotics, but when you start including compounds that aren't even antibiotics, I'd like to see that it's justified with research.

I'm not advocating putting these things in all of our soaps and constantly sanitizing. I'm just questioning the position that it leads to antibiotic resistance. I don't think it will.

[simster]

Originally Posted by WarmNPrickly

Triclosan is not an antibiotic. It is an antibacterial. I am not certain that resistance to triclosan has been demonstrated outside the laboratory, and even if it did, that this resistance would translate to methicillin resistance.

I'm not a doctor, but methicillin resistance does not usually translate to tetracycline resistance which doesn't translate to vancomycin resistance. If the antibiotics don't cause cross resistance between classes, then how likely is it that something different enough to not be classified as an antibiotic, cause resistance to compounds even less related?

I do understand though, that MDR bacteria can be facilitated with ABC transport over expression. I think, in this way, resistance can be effective across classes of antibiotics, but when you start including compounds that aren't even antibiotics, I'd like to see that it's justified with research.

I'm not advocating putting these things in all of our soaps and constantly sanitizing. I'm just questioning the position that it leads to antibiotic resistance. I don't think it will.

I see it not so much that we are creating 'antibiotic resistant germs' in this case, but moreso that we are not allowing our own immune systems to build resistance to those germs/etc - thereby weakening our own resistance to them.

[Irishman]

I don't believe anyone is making the claim that triclosan or alcohol rubs will cause increased resistance to antibiotics.

Rather, the claim as I understand it is that in the same way that overuse of antibiotics causes resistance to those antibiotics to develop, so overuse of triclosan might cause resistance to triclosan to develop, and overuse of alcohol rubs could cause resistance to alcohol to develop.

I read the part about one site vs multiple sites, but need it reparsed for me. What kind of sites? Where are the sites? How do sites matter? Also, a tutorial on how a biocide is different than an antibiotic would be useful. It's all fine and dandy to say "alcohol and triclosan are antiseptics, not antibiotics", but if you don't explain why that makes a difference, you aren't really addressing the question.

One difference that makes some sense to me is that antiseptics (biocides) work by breaking the cell membrane, thus rupturing the cell. The cell dies immediately. Wheras antibiotics attack the "inner workings" of the cells, perhaps at the DNA level, allowing the cells to keep living for a time as they work, kinda like humans and our immune systems.

But I'm making that up. Someone who actually knows should explain, please.

Because I'm annoyed I can't find liquid soap that doesn't have triclosan*, so I'd like to take comfort in the fact that overabundance of triclosan is not causing future problems to be worse. But right now I can't, because I don't know enough.

-----
*Apparently a lot of people don't like to wash their hands with soap bars. The bars get squishy or dirty or whatever, and it squicks people certain ladies out. So I accede to the wish to not be squicked out, and lament the overuse of triclosan.

[WarmNPrickly]

Originally Posted by Irishman

I read the part about one site vs multiple sites, but need it reparsed for me. What kind of sites? Where are the sites? How do sites matter? Also, a tutorial on how a biocide is different than an antibiotic would be useful. It's all fine and dandy to say "alcohol and triclosan are antiseptics, not antibiotics", but if you don't explain why that makes a difference, you aren't really addressing the question.

This is a good point, and I shouldn't pretend that I know the actual difference myself. I was kind of hoping someone with better knowledge would step in.

One difference that makes some sense to me is that antiseptics (biocides) work by breaking the cell membrane, thus rupturing the cell. The cell dies immediately. Wheras antibiotics attack the "inner workings" of the cells, perhaps at the DNA level, allowing the cells to keep living for a time as they work, kinda like humans and our immune systems.

This is what I think. I also think that antiseptics tend to be used in higher concentrations. Certainly bleach, as a potent oxidant, will mess with all kinds of systems. Triclosan is a phenol and likely messes with the cell membrane as you suggest. I'm certain that they can develop resistance to these things. After all, they can make bacteria that are extremely resistant to arsenic. I'm not certain that this resistance is a threat.

[MacLir]

Originally Posted by Bearcat69

Excuse me if this is slightly off-topic, but I couldn't resist mentioning the latest in germaphobia: the no-touch soap dispenser. The advertising preys on the fear of germs residing on that nasty pump handle.

We got some of those at work. However, in a case of taking logic a little too far, they put one up right next to the entry door. Motion activated, remember?.

So as you approached the door, just about the time you were opening it, the unit would greet you by - well - ejaculating at you. The act of opening the door would line you up just right.

Lasted about three days before it was forcibly removed.

[TSBG]

Irishman, I buy Dr. Bronner's or the Trader Joe's castile soap and use it to refill soap dispensers. I dilute it with an equal amount of water. I do this not because of the Triclosan but because I really dislike the scent of most pump soaps. One can find unscented refills for some brands, sometimes, but I can always get Bronners/TJ's brand and I don't mind the mint scent.

[Chronos]

We got some of those at work. However, in a case of taking logic a little too far, they put one up right next to the entry door. Motion activated, remember?.

So as you approached the door, just about the time you were opening it, the unit would greet you by - well - ejaculating at you. The act of opening the door would line you up just right.

Lasted about three days before it was forcibly removed.

Please tell me that it made it onto YouTube in those three days.

[debbiemoore]

Originally Posted by fgasparini

Wouldn't a thorough hand-washing also kill "beneficial" bacteria? And what's to prevent bacteria from evolving "soap resistance"?

The main problem is more to do with the inadequate use of sanitizers together with the hype being built up around a level of sterility which is not achievable (and probably not necessary for good health either...).

Sanitizers need time to work on killing bacteria whereas soap alters surface tension of organic matter and just melts bacterial membranes - it is almost instantaneous. But it is killing on a structural plane, not internal where bacteria could resist. There is not much chance of developing resistance to soap, it's like humans developing immunity against a shotgun.

Somehow people have got into the habit of just rubbing sanitizers on their hands for a few seconds and assuming that this is better than soap, and this is simply not true. The average cosmetic hand sanitizer is fairly weak and you would need to rub with lots of gel for about 20 minutes to get the same effect as using soap. If you only kill a percentage of bacteria you tip the balance and give resistance a larger playing field. The biggest problem with sanitizers is that they take out the weak ones first and assumes there is enough on the hands for a long enough period to take out the stronger, resistant strains too, and that just doesn't happen.

Yes with soap the good guys would go down too but the point is they would all have an equal chance of being wiped out and you are more likely to keep the balance healthy.

We're never going to rid the world of bacteria - that would be counterproductive to our health (plus how else would we clean up our oil spills...), but we can at least try to get on with them and keep the balance in check, and that means unless preparing for surgery, we should not being paranoid about the tiniest germ on our hands.

[DA FUZ]

When you use hand sanitizer it indisciminately kills all the microrganisms on your skin. There are healthy bacteria on your skin that cause no harm but when they are removed it creates an environment in which pathogenic organisms may mulitiply causing disease.

[Irishman]

Originally Posted by debbiemoore

Sanitizers need time to work on killing bacteria whereas soap alters surface tension of organic matter and just melts bacterial membranes - it is almost instantaneous. But it is killing on a structural plane, not internal where bacteria could resist. There is not much chance of developing resistance to soap, it's like humans developing immunity against a shotgun.

Can you provide a cite that soap kills bacteria, and that it does so by melting membranes? It is my understanding that soap does not kill any bacteria. The reason we wash with soap and water is to dislodge the bacteria with the dirt through mechanical action. Hands rubbing together knocks stuff off hands. Soap helps remove stuff from hands. Hand sanitizers actually kill germs - if the sanitizer is in contact long enough.

From http://www.learnwell.org//handhygiene.htm

3.2 Plain (Non-Antimicrobial) Soap
Soaps are detergent-based products that contain esterified fatty acids and sodium or potassium hydroxide. They are available in various forms including bar soap, tissue, leaflet, and liquid preparations. Their cleaning activity can be attributed to their detergent properties, which result in removal of dirt, soil, and various organic substances from the hands. Plain soaps have minimal, if any, antimicrobial activity. However, handwashing with plain soap can remove loosely adherent transient flora. For example, handwashing with plain soap and water for 15 seconds reduces bacterial counts on the skin by 0.6--1.1 log10, whereas washing for 30 seconds reduces counts by 1.8--2.8 log10.

The average cosmetic hand sanitizer is fairly weak and you would need to rub with lots of gel for about 20 minutes to get the same effect as using soap.

Please provide a cite that it takes 20 minutesfor hand sanitizer to kill germs. Even commercial public sanitizer, vs hospital/doctor grade.

From same cite above:

Alcohol-based products are more effective for standard handwashing or hand antisepsis by HCWs than soap or antimicrobial soaps. In all but two of the trials that compared alcohol-based solutions with antimicrobial soaps or detergents, alcohol reduced bacterial counts on hands more than washing hands with soaps or detergents containing hexachlorophene, povidone-iodine, 4% chlorhexidine, or triclosan. In studies examining antimicrobial-resistant organisms, alcohol-based products reduced the number of multidrug-resistant pathogens recovered from the hands of HCWs more effectively than did handwashing with soap and water.

[snip]

The efficacy of alcohol-based hand-hygiene products is affected by several factors, including the type of alcohol used, concentration of alcohol, contact time, volume of alcohol used, and whether the hands are wet when the alcohol is applied. Applying small volumes (i.e., 0.2--0.5 mL) of alcohol to the hands is not more effective than washing hands with plain soap and water. One study documented that 1 mL of alcohol was substantially less effective than 3 mL. The ideal volume of product to apply to the hands is not known and may vary for different formulations. However, if hands feel dry after rubbing hands together for 10--15 seconds, an insufficient volume of product likely was applied. Because alcohol-impregnated towelettes contain a limited amount of alcohol, their effectiveness is comparable to that of soap and water.

Bold and underline added. Now they state that 15 seconds is not long enough, but note that they are still discussing seconds. Nowhere did minutes even come under consideration.

Oh,

Typically, log reductions of the release of test bacteria from artificially contaminated hands average 3.5 log10 after a 30-second application and 4.0--5.0 log10 after a 1-minute application.

That's 99.9% after 30 seconds, and 99.99% to 99.999% after 1 minute. Nowhere near 20 minutes.

If you only kill a percentage of bacteria you tip the balance and give resistance a larger playing field.

That is the question: do hand sanitizers promote bacteria that are resistant to those sanitizers? So far the evidence says that alcohol versions do not because they are more volatile/reactive/whatever, but triclosan has a more narrow band of action. While there is no evidence shown so far that resistance is developing, it is not impossible.

Originally Posted by DA FUZ

When you use hand sanitizer it indisciminately kills all the microrganisms on your skin. There are healthy bacteria on your skin that cause no harm but when they are removed it creates an environment in which pathogenic organisms may mulitiply causing disease.

From link previously provided by Jackmanii:
http://scienceblog.com/10882/hand-hy...isinformation/

1. Good germs are microorganisms normally found on human skin and bad germs are pathogenic (disease producing) microorganisms.
2. The numbers of good germs and bad germs on the hands are variable from one person to the next but remains relatively constant for each individual.
3. Good germs cannot protect you against bad germs. Anyone can become contaminated with bad germs (pathogens).
4. Bad germs (pathogens) do not always cause infections and good germs in the wrong place can cause infections.