Tuesday, July 31, 2012

Benign bacteria help T cells signal skin infection

Benign bacteria on our skin partner with T cells to alert the immune system to the presence of dangerous pathogens, according to research recently published online in the journal Science.

The NIH press release explains the science very well, probably better than I could, so I have copied their text below.

The most relevant point that I can see is that this work shows that microbes living on healthy skin have an important role in our immune system. It's a philosophical question whether the microbes are separate from us--or are part of us, even though they don't share our DNA. If you overuse antibiotic ointments (that is, apply them for periods longer than required to treat an infection), you are killing off helpful microbes and weakening your immune response.
NIH team describes protective role of skin microbiota
Commensal bacteria and immune cells work together to fight harmful microbes

WHAT: A research team at the National Institutes of Health has found that bacteria that normally live in the skin may help protect the body from infection. As the largest organ of the body, the skin represents a major site of interaction with microbes in the environment.

Although immune cells in the skin protect against harmful organisms, until now, it has not been known if the millions of naturally occurring commensal bacteria in the skin—collectively known as the skin microbiota—also have a beneficial role. Using mouse models, the NIH team observed that commensals contribute to protective immunity by interacting with the immune cells in the skin. Their findings appear online on July 26th in Science.

The investigators colonized germ-free mice (mice bred with no naturally occurring microbes in the gut or skin) with the human skin commensal Staphylococcus epidermidis. The team observed that colonizing the mice with this one species of good bacteria enabled an immune cell in the mouse skin to produce a cell-signaling molecule needed to protect against harmful microbes. The researchers subsequently infected both colonized and non-colonized germ-free mice with a parasite. Mice that were not colonized with the bacteria did not mount an effective immune response to the parasite; mice that were colonized did.

In separate experiments, the team sought to determine if the presence or absence of commensals in the gut played a role in skin immunity. They observed that adding or eliminating beneficial bacteria in the gut did not affect the immune response at the skin. These findings indicate that microbiota found in different tissues—skin, gut, lung—have unique roles at each site and that maintaining good health requires the presence of several different sets of commensal communities.

This study provides new insights into the protective role of skin commensals, and demonstrates that skin health relies on the interaction of commensals and immune cells. Further research is needed, say the authors, to determine whether skin disorders such as eczema and psoriasis may be caused or exacerbated by an imbalance of skin commensals and potentially harmful microbes that influence the skin and its immune cells.


  1. Hi there,

    Just discovered your blog--one of the better ones out there, so thank you for your contributions. Very up to date on the science (I study public policy really, but spend my time reading med journals to help cope with my eczema which has been off the charts this year).

    Anyway, I have been searching for a "probiotic" for the skin for ages. If you ever come across anything could you please post as I think this is the answer to my staph woes...been on Keflex (Cheplasporin) antibiotic over 20 times in 2 years, maybe more I lost count. I get infected hair follicles, usually only one at a time that my body cannot win on its own and they develop into large boils.

    Yes, too much information. I am desperate to find a way to get my skin flora back in balance. I agree with all the skin barrier concerns and my derm is 100% on board, we are trying to treat eczema through barrier repair, but the heavy creams clog the pores and the staph thrives...

    Thank you again for your blog, I am watching for new stuff from you here on in.

    On a side note, I read some articles about new evidence linking H3 receptors with skin itch in dermatitis patients. Current anti-histamines target H1 and some H2, but none H3. Interesting potential there for itch management I think...


  2. I have a similar ongoing battle with staph although not as serious as yours. Not fun, and nobody wants to be on antibiotics.

    Of course I'll post anything I see on the topic. This isn't probiotics, but have you tried bleach or vinegar in a bath? (with appropriate dilution of course.) Bleach might keep the pathogens down. Our skin is not acidic enough and pH seems to be important for the microbial community.

    In my own experience, extensive overuse of strong steroids can lead to a staph outbreak. Also, when I was young and ignorant, I used to save antibiotic capsules and self-medicate when I felt like it. That was not a good idea!

    Best of luck.

  3. Skin infection is really painful. Sometime we are not able to understand why it is happening. Your blog is readable.