Can general soap kill bacteria?

I have read that general soap can kill bacteria by opening holes in the bacterial membrane.

http://questions.sci-toys.com/node/90

However, I found some articles as well saying that it cannot.

http://goaskalice.columbia.edu/answered-questions/does-soap-kill-germs

There seems split answers among experts,
so I would like to know which one is correct.

Could anyone advise me?

Thanks.

4

Answers


  1. shigeta
    0 Votes

    Soap kills nearly all the bacteria it comes into contact with by dissolving the bacterial membrane. Some viruses with protein coats can resist soap, but many viruses have similar membranous coats (like HIV) and are usually disrupted by soap. I’m sure it washes some away too, but to say they don’t kill bacteria is misleading. In the end, though, they are gone.

    Antibacterial soap with triclosan does not kill bacteria on contact and are no more effective than if they had no triclosan at all. That’s actually a good thing since really using an antibiotic would probably accelerate antibiotic resistant bacteria which is a serious – probably catastrophic public health failure. A recent study showed that killing bacteria by soaking with triclosan took 9 hours to start showing an effect.

    To achieve full sterility, surgeons bathe their gloves in iodine (see details in the comments below) and their instruments will be sterilized by heating them beyond the boiling point in an autoclave under pressure. That’s useful when you are breaching the skin in surgery, but the skin needs some bacteria to be healthy long term and works well to fend off bacterial infections.

    Your confusion seems to come from finding a page full of errors. Alice didn’t really do her homework.

  2. akaDrHouse
    0 Votes

    Soap is a detergent. It actively emulsifies the bacterial membrane, thus killing them by breaking this membrane. So yes, soap kills bacteria. Some bacteria are more or less resistant to this depending on the constituents of their lipid-bilayer membrane.

    The reason why soap doesn’t hurt your own cells is that for the most part, your outer skin layer is comprised of dead cells that have numerous cross-linked keratin filaments mixed with oils from your sebaceous glands that provide a nice nearly airtight, watertight barrier.

    Excessive hand-washing or washing hands with stronger detergents can actually get rid of this protection and break down the barrier mentioned in the prior paragraph, leading to dry and cracked skin.

  3. theforestecologist
    0 Votes

    Generally, the goal for using non-antimicrobial soap is simply to pick up and remove organisms and dirt from our skin. This is achieved first by the soap chemically bonding to certain molecules (i.e. oil or lipids). Second, friction from rubbing mechanically and rinsing with water pick up and removes the soap and chemically bonded particles. Thus, the more soap and the longer the hands are rubbed together, the less oil and microbes left on your hands.

    For a more scientific answer:

    Soap is a detergent, meaning one side of the molecule is hydrophilic (likes water), and the other is hydrophobic (likes oil). Cellular membranes are also made out of a dual sided hydrophobic and hydrophilic molecule called a lipid. The soap solvates the hydrophobic parts of the lipid cell membrane, and you’re left with a mixture of lipids & oils suspended in the soap. These are washed away when you rinse with water (imagine how cooking oil floats on top of water).

    For another (longer) response to this question see here.


    Comments on website credibility:

    I’ll also comment that at any point that you do an online search, you REALLY need to pay attention to the source of the information you’re looking at. The internet is crawling with misinformation and inaccuracies — often represented as fact or even presented by a so-called ‘expert’! Typically, .edu websites (from academic institutions) are MUCH MUCH more trustworthy than .com, .org, etc. because they typically originate from some kind of peer-review or life-long study of a topic.

    Be cautious, however, that you don’t end up on a .edu page that contains a student’s (or other non expert’s) thoughts/opinions/or (possibly wrong) response to a question. Further, unfortunately it’s not always this simple, as .org or .com info isn’t necessarily wrong.

    If you want to increase your odds of finding the most accurate information, go straight to the peer-reviewed literature (start a search here). If this is too daunting a task or if you can’t find what you’re looking for, then I’d suggest focusing on .edu websites for info. You can use the “site:” operator in a Google search to specify a domain — specifically, if you’re looking for high-quality references, you could use site:.edu to only pull up results from .edu domains.

    That being said, I think it’s clear that your first link is not nearly as trustworthy as your second, and in this case can be dismissed as internet misinformation.

    Hope this helps!

  4. ofornes
    0 Votes

    Well, I would say regular soap does not kill bacteria unless active antimicrobial ingredients have been added to it. In fact, when rubbing your hands with soap, once rinsed away with water, what you are doing is removing the fat from your hands together with microbes.

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