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Anna Crist

student researcher , University of Oregon

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Purell now, Bacteri-ell later?

The hygiene hypothesis, the idea that “too much cleanliness prevents the development of a well-balanced immune response”(Sironi and Clerici, 2010), has received a lot of support and also criticism. It has recently been challenged by the hypothesis of “early immune challenge”, which states that a lack of appropriate immune stimulation during early childhood might account for the increased development of allergies in industrialized countries (Kramer et al, 2013). This proposal places less emphasis on excessive hygienic practices and focuses more on the insufficient exposure to specific environmental microbes, particularly those from non-urban environments, as the reason behind the rise of atopic disease. While different, both hypotheses point to the beneficial health affects of some microbes.

What do you think is the reason for increased allergy levels in industrialized countries? Do you think that a concoction of the “right” microbial species in the form of a lotion, drink, or inhalant (aka "Bacteri-ell") could be a future replacement for natural exposure to beneficial microbes?
Instead of using hand sanitizers like Purell, do you see a future where people from some regions of the world are unsanitizing their hands with “Bacteri-ell”?


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    Apr 30 2013: I'm going to have to play the devil's advocate for this question.

    Although, studies support this theory, to me the premise alone seems a little unrealistic. I know very few people that use Purell (or similar) products on a very consistent basis, that one could consider over use. The moment a user's hands dry and they touch something (a book, a door handle, a railing, a chair, etc...) the bacteria living there are immediately transferred to the skin. Essentially, even a handshake would completely reverse the bacteria massacre that said individual had just preformed. It seems unrealistic that anybody could have sterile hands 24/7.

    I would also like to bring up an alternative hypothesis.that perhaps the disruption of skin microbiota is not significant in the development in these allergies. In the specific study cited by Anna, the researchers looked a particular antimicrobial chemical, Triclosan. They correlated its presence with allergic reactions. Although this revelation supports the conclusion reached by the authors, it doesn't rule out one basic alternative. Perhaps the Triclosan itself is causing an increase in allergies by aggravating the immune system. Studies have shown Triclosan to cause allergic reactions in some individuals.

    This conclusion would tie in well with another hypothesis, the pool chlorine hypothesis. The pool chlorine hypothesis suggests that an increase in time spent in chlorinated pools is correlated with an increase in asthma rates. The authors of this hypothesis suggest that is the chlorine per se that is causing the asthma.

    I believe that perhaps this is a similar situation to that involving Triclosan and that it is not the lack of microbes that are causing the problems, but the Triclosan itself.

    -Bhutani, T.; Jacob, SE. (May 2009). "Triclosan: a potential allergen in suture-line allergic contact dermatitis".
    -Campbell, L.; Zirwas, MJ. (Dec 2006). "Triclosan". Dermatitis
    • Apr 30 2013: I agree with Ben, I don't think people are over using Purell or any other antibacterial substances, nor do I think we should cut down on using them or the cleanliness methods we have been taught. For example if people in food service started washing their hands less, I think many more people would get sick then the amount that would build up a stronger immunity. I think one of the biggest reasons people are getting sick more often is due to overuse of antibiotics. whether it's a doctor prescribing an antibiotic for a viral infection or a parent giving a child medication for something their body can fight on their own, people's immune systems are getting weaker. Instead of looking at adding bacteria to a person with a weaker immune system, maybe we should start by decreasing the medication use and then we will see a decrease in people with so many allergies and other serious conditions.
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        Apr 30 2013: I don't think that anyone is advocating that people in the food service industry start washing their hands less. I agree with your point that antibiotics is a contributing factor, however I think that it is a lack of early exposure to microbes that can cause lasting health consequences.
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          Apr 30 2013: I agree, we need exposure to all kinds of microbes at an early age so that our body's natural immune responses can be become stronger. It would be so cool to one day have the research and knowledge about what microbes are vital to be exposed to at an earlier age. If we could obtain this knowledge, we could facilitate exposure in people that were born with compromised immune systems, such as premature babies or cesarean births.
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          Apr 30 2013: Yes! Exposure to the microbial environment is extremely important in development of a child's immune system. Microbes naturally found in soil may be linked to releasing serotonin, changing a persons mood.
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          Apr 30 2013: Noel, that is very interesting! There may be a link between immune system imbalances and mood disorders.
        • Apr 30 2013: That is probably very true Eleni! I am not against exposing people to more microbes. I am exposed to all kinds every day at my little zoo of a home! I'm also thankful I have Purell and antibacterial soaps to use after exposing myself to these other microbial environments because it keeps me from getting sick. I think people go from one extreme to the next when things are discovered so my fear is if it's pushed that we are "too clean" and need more exposure to bacteria that people will start being a lot less clean.
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      Apr 30 2013: Thanks everyone!
      Ben- What I think you are missing that Eleni and Ashleigh pointed out is that exposure to microbes at an early age is what is important. I am certainly not trying to suggest that people have sterile hands because of overuse of Purell, "Bacteri-ell" is just a play on words. I am proposing that a lack of exposure to certain key microbes at an early age, due to an overall less natural environment in industrialized regions, is the cause behind increased frequency of allergies. You raise an interesting point that a handshake could reverse a lack of exposure to certain microbes. Maybe people who have a more complete "microbe cloud" (in the words of Jonathan Eisen), could serve as "microbe donors" to children who don't have access to the mrobe diversity in nature, such as that you would find on a farm.

      Your idea that chlorine and Triclosan themselves are the cause of allergies is definitely something to consider.

      Asleigh: Your comment is exactly what I am getting at! :) My idea definitely relies on our future ability to gain the knowledge you mentioned.

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