Bacteria resistance?

April 9, 2008 10:52 AM

Tell me about antisceptic hand washes and building resistance in microorganisms.

My workplace is putting a few new antisceptic hand wash stations on every floor. This has caused a rift amoung coworkers, half saying that these antisceptic washes increase resistance in bacteria and half saying that because the wash is alcohol based it does not contribute to super bugs.

Can anyone with more/better info shed a little light?

posted by Cosine to work & money (19 comments total)

You mean like this?

Plain soap as effective as antibacterial but without the risk
Antibacterial soaps show no health benefits over plain soaps and, in fact, may render some common antibiotics less effective, says a University of Michigan public health professor.
posted by Cool Papa Bell at 10:59 AM on April 9, 2008

Oh, but there's this:
Other antiseptic products on the market contain different active ingredients, such as the alcohol in hand sanitizers or the bleach in some antibacterial household cleaners. Aiello's team did not study those products and those ingredients are not at issue.
posted by Cool Papa Bell at 11:00 AM on April 9, 2008 [1 favorite]

If the wash is indeed alcohol-based and does not contain triclosan or other antibacterials, then your coworkers who say it won't contribute to resistance are correct. Even if it does contain triclosan, the risk is minimal. A recent study found the following:

(1) There is evidence that, in the laboratory, exposure to antibacterials such as triclosan can lead to higher pethogen resistance.

(2) "No evidence suggests that use of antibacterial soap containing 0.2% triclosan provides a benefit over plain soap in reducing bacterial counts and rate of infectious symptoms in generally healthy persons in the household setting."

(3) "Our findings suggest that household use of antibacterial cleaning and hygiene products for a 1-year period is not a significant risk factor for increasing antimicrobial drug–resistant organisms on the hands of persons in the home."

In plain English: antibacterial soaps do not seem to lead to increased pathogen resistance in the short term, BUT they are no more effective at preventing the spread of infectious diseases than regular old soap.
posted by googly at 11:02 AM on April 9, 2008

So far, alcohol-based hand sanitizing liquid hasn't been found to breed superbugs. If that's what your office is putting in, it should be fine.

Antibacterial soaps, most commonly containing triclosan, are the ones you want to avoid if you're concerned about generating a new, superior strain of bacteria. And as Cool Papa Bell cites above, they don't seem to really help much anyway.
posted by mumkin at 11:05 AM on April 9, 2008

What you need is for you to become resistant to the bacteria. The washes keep you from encountering the bacteria and prevent your immune system from developing a response.
posted by Ironmouth at 11:06 AM on April 9, 2008

Ironmouth: I agree with you actually, but that is a separate issue.
posted by Cosine at 11:08 AM on April 9, 2008

What you need is for you to become resistant to the bacteria. The washes keep you from encountering the bacteria and prevent your immune system from developing a response.

Exactly. In the old days the saying for this was "You've got to eat a peck of dirt before you die." In other words, let kids play, get dirty and eat dirt -- it won't kill them. And in fact, it made them healthy. A baby reared in a completely sterile environment for the first five years of her life would get fatally ill the first week of kindergarten from exposure to pathogens all the other kids are already immune to.

I recently traveled to a Central American country with a group of Americans who seemed to be passing around a bottle of hand sanitizer about every half hour for fear of contracting something. Me, I washed my hands at all the normal times; didn't have a sniffle. It could be that's because I eat stuff that falls on the floor of my house; I don't wash fruits and vegetables unless I have company, or if they seem to be a little gritty; I grab the handle of the men's room on my way out the door without worrying about it; and basically I just don't get phobic about dirt or germs. And I have not called in sick more than twice in 30 years.
posted by beagle at 11:18 AM on April 9, 2008 [1 favorite]

Antisceptic hand washes don't kill germs. They simply convince you that they do. Placebo effect.
posted by weapons-grade pandemonium at 11:27 AM on April 9, 2008

"I don't wash fruits and vegetables unless I have company..."

The problem with vegetables isn't dirt and germs it's pesticides, herbicides and fungicides.
posted by 517 at 11:31 AM on April 9, 2008

Bacteria are not going to become immune to immersion in alcohol or bleach.

(Whether there is any benefit to this project is another question)
posted by winston at 11:35 AM on April 9, 2008 [1 favorite]

IAAMAASB (I Am a Microbiologist And a Structural Biologist)

Your coworkers are probably talking about how the prevalence of antibiotics in various consumer products contributes to the rise of antibiotic resistance in bacteria. They're not wrong about that part, but most alcohol-based hand sanitizers rely on the action of alcohol, not antibiotics. The difference with respect to resistance lies in how these things kill or inhibit bacteria.

Antibiotics are some chemotheraputic agent, usually a small molecule, that is taken up by the bacteria and disrupts some essential process. Some of them mimic cell wall components, but instead weaken the bacterial cell wall and allows it to break. Others disrupt cell processes like DNA or protein production, causing cell death. In most cases, however, the antibiotic has to be first taken up by the bacteria and then incorporated into the process that it will disrupt. Triclosan, which is found in many soaps, acts by inhibiting fatty acid synthesis. Bacteria can develop resistance to these antibiotics by preventing the import of the antibiotics, or creating enzymes which break down the antibiotics before it can do anything, or just bypassing the process that the antibiotic targets, amongst other ways.

Alcohol, and some other microbicidals like chlorine and steam heat, don't target any specific system. They attack the structure of the bacteria itself by cooking it (denaturing, in biochemical terms), causing the proteins to coagulate. Any life is mostly constructed of proteins (though many bacteria have tough non-protein cell walls). The structure of these proteins is important to their function, so if you disrupt their structure they tend to lose that function. It is difficult for bacteria to acquire a defense against this type of disruption. Enzymes are usually themselves made of proteins, and would be broken down by the alcohol. Bacteria have many important cell membrane proteins which would be disrupted by alcohol. It is this combination of non-specificity and attack on proteins that makes alcohol so effective.
posted by Mercaptan at 11:39 AM on April 9, 2008 [9 favorites]

What you need is for you to become resistant to the bacteria. The washes keep you from encountering the bacteria and prevent your immune system from developing a response.

If this was true, then nurses and doctors would become LESS resistant to all the different bacterias that they encounter as time goes on. Circumstantial evidence would indicate that this isn't true, or our healthcare shortage would be much worse than it already is, no?
posted by SpecialK at 12:47 PM on April 9, 2008

Previously on AskMe: See my comment here and the one from ikkyu2 that follows it.
posted by chrisamiller at 1:00 PM on April 9, 2008

SpecialK: Actually that's not correct, hospital staff aren't using antibacterial washes for their own health, they are using it to protect those patients whose immune systems are already compromised.
posted by Cosine at 1:40 PM on April 9, 2008

googly as to your point 3- triclosan is being found in ground water (and even women's breast milk). In the ground water it will be available in low doses to cull those bacterium most susceptible. While not "increasing antimicrobial drug–resistant organisms on the hands of persons in the home" it is easy to imagine this low level exposure increasing antimicrobial drug–resistant organisms in the wider enviroment.
posted by pointilist at 9:48 PM on April 9, 2008

The wikipedia article on triclosan cites work that disproved the thesis that Triclosan contributes meaningfully to drug resistance. The pseudomonas MDR efflux transporter can pump triclosan out of the bacterial cell to some extent, but in the high concentrations that are used that ability is overwhelmed and the bacteria is destroyed immediately.

Antibiotic resistance is a problem, but bacteriocidal agents are not the cause of that problem. Improper use of antibiotics is the cause of that problem.

Hand washing and hand rinses are proven in healthcare settings to reduce the spread of harmful infections.
posted by ikkyu2 at 12:31 AM on April 10, 2008

Triclosan bears a disturbingly close structural resemblance to dioxin, and can in fact be converted to dioxin by exposure to ultraviolet light:

Abstract
The direct photolysis of triclosan (5-chloro-2-(2,4-dichlorophenoxy)phenol), an antimicrobial additive commonly detected in surface waters, is studied. It is found that 2,8-dichlorodibenzo-p-dioxin (2,8-DCDD) is produced in both buffered and natural (Mississippi River) water with yields ranging from 1 to 12% under a variety of conditions. This result indicates that triclosan is likely converted to 2,8-DCDD in sunlight-irradiated surface waters.
posted by jamjam at 5:21 PM on April 10, 2008

The antisceptic properties are breaking down--the sceptics are back.
posted by weapons-grade pandemonium at 10:16 PM on April 12, 2008

ikkyu2 I don't depute what you are saying regarding the high concentrations that are used. I am concerned about the low concentrations available in the wider enviroment.
posted by pointilist at 10:28 PM on April 15, 2008