This is a guest post by SnoWhite of Finding Joy in My Kitchen.
This week there has been a focus on getting the antibacterial soaps out of our homes. As a biologist, I am excited by this because our overuse of these soaps actually contributes to bacteria no longer being killed by antibiotics.
How does this process work? How does our use of antibacterial soaps contribute to antibiotic resistance?
1) Not all bacteria are genetically identical. Even though on the surface bacteria (for example, E. coli) seem identical, there is a lot of variation in the population. Some E. coli bacteria have different genes than others. Some have a gene that makes them resistant to antibiotics, some don’t.
2) The bacteria’s environment matters. When E. coli bacteria are not exposed to antibiotics, these genetic differences in their resistance to antibiotics really does not matter. In this environment, all bacteria have a similar chance of surviving and reproducing offspring (read: our normal hand soap is an equal opportunity bacteria killer). However, when E. coli are exposed to an antibiotic, say triclosan in our hand soap, the variation in the population of E. coli creates a difference.
Exposure to antibiotic (e.g., Tricolsan) Case #1: When E. coli are exposed to triclosan, those that do not have the gene for being able to tolerate triclosan will die. These bacteria will no longer be able to reproduce more bacteria.
Exposure to antibiotic (e.g., Tricolsan) Case #2: When E. coli are exposed to triclosan those that DO have the gene for antibiotic resistance will survive. These bacteria pass on their genes to their offspring and their offspring then are resistant to our antibiotic.
3) The result: A “Super Bug” Population of Bacteria. Antibiotic resistant bacteria are often termed “super bugs” because they are unable to be killed off by our antibiotics. This “super bug” population of bacteria is now resistant to triclosan, because all the bacteria that were not resistant were killed off and unable to reproduce.
In both Case #1 and Case #2 above, it is important to realize that bacteria are not learning to fight back. Just like you and I have no control over our genetic make-up, bacteria cannot change their genetic make-up in response to a change in their environment. Bacteria reproduce so quickly that those without the gene for resistance die and the non-resistant gene quickly disappears from the population and the result is what appears to be a population of bacteria that are fighting back against our antibiotics.
By cutting down on our antibacterial soap use, we can help prevent these changes in the bacterial population. When we stop using soaps with Triclosan, we are no longer just killing bacteria that can be killed by the antibiotic, we have an equal chance of killing any bacteria in the population! This helps because bacteria without the resistance gene can remain in the population and reproduce offspring so that this gene remains in the population.
Thank you, SnoWhite, for clearing up my own misconceptions about bacterial resistance and sharing with the KS community! Dear readers, do visit Finding Joy in my Kitchen, as SnoWhite takes more beautiful food pictures than I do and has a wealth of recipes. I’ve tried a handful of hers and have not been disappointed! She also just happens to attend my alma mater (Go MSU!).
My thought? With all the warnings about making sure we’re not using antibiotics without reason, it’s striking to hear Triclosan, an ingredient in soap that is used daily by people who are not sick, called an antibiotic. That is 100% true – so remember that when you’re considering buying antibacterial soap. Unless someone in your home is disastrously ill, you don’t need it.
This post supplanted the Great Debate on soaking grains, by the way. It was just more timely. Thanks for your patience on that thorny issue!
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Photo from kaibara87.
That was an incredibly helpful way of describing the issue! I think I can explain it better to my kids. In a sense, we’re helping with natural selection, but we’re the ones doing the selecting because of our behavior. Ugh!
.-= Barb@My Daily Round´s last blog ..tomorrow: meatless meals lenten carnival =-.
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SnoWhite Reply:
March 26th, 2010 at 9:58 am
that is exactly right! We are the selecting agent in this case… so — we have a positive role to play too!
.-= SnoWhite´s last blog ..Deep Dish Pizza =-.
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This makes much more sense!
.-= Annie´s last blog ..Pre-dinner snack =-.
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Thanks for this great, very informative post. This totally makes more sense to me now, and I feel that I can better explain it to others too.
It kind of seems like triclosan is doing the exact opposite of what we want it to do. People who are germ-o-phobe and using antibacterial products should be more scared of the bacteria that they are keeping around!
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I love science. I am relieved to find the explanation that the bacteria are not “fighting back,” or “evolving resistance,” but rather that they already had (were originally designed with) the genetic deficiency. I wish Sno had also mentioned fitness cost. The bacteria in case #2 are actually weaker than the bacteria in case #1. Even though we euphemistically and quite incorrectly call them super-bugs, they are actually mutant strains who are missing an enzyme that makes them less fit than the case #1 strain. Drug-resistant bacteria might be a more accurate description. If you reintroduce case #2 bugs into a culture of case #1 bugs, the case #2 bugs will quickly be outnumbered and squeezed out by the stronger strain that does not have the genetic deficiency.
.-= Gregg´s last blog ..The Power of a Praying Wife =-.
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I know this is an old post, but I found it after reading about Homemade Soap at amylovesit.com… What you are saying makes sense to me, but is this true for everyone? My daughter gets reoccuring staph infections on her bottom, she is 4 years old and this has been going on for 2 years. I started out taking her to the doctor and getting antibiotics, but they always came back. Finally after internet searching I decided antibiotics were not the answer and use antibacterial soap always for body, hands, and cleaners and a weekly hibiclens bath. Every few months one still pops up and I shift things into overdrive and she gets 3 or more baths a day until it is gone. No doctor or antibiotics… So in this situation am I doing the wrong thing with using all antibacterial soaps?? TIA!
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Katie Reply:
January 31st, 2011 at 2:50 am
Jen,
First, of course let’s remember that I am in no way a health professional. I would much rather see, personally for your daughter’s sake, antibacterial soap used rather than antibiotics themselves. My opinion. I know so little about staph infections – other than that they are nothing to mess with – but I wonder if a sugar detox and some heavy duty probiotics would help? If folks are getting regular (internal) bacterial infections, it’s often a sign that their intestinal flora (the healthy bacteria that make our systems work) is out of balance. It’s possible that external staph infections could be helped by getting more probiotics into the body (and cutting the sugar so the bad guys don’t have anything to eat), but I’m really not sure. Might be worth more consulting with Dr. Google!
I’m really pleased that you found a way to avoid antibiotics- what a good mama you are! And asking questions is always a helpful thing, too. Good luck tackling these bad guys once and for all!
Katie
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