Science and Medicine

Washington Post staff writer Rob Stein was online to discuss Monday's Science Page article about skin bacteria at 11 a.m. ET on Monday, Feb. 12.

He writes about the the first molecular analysis of the bacteria living on one small patch of human skin, which revealed that human skin is populated by a diverse assortment of bacteria, including many previously unknown species. Read the rest of the story here: Close Look at Human Arm Finds Host of Microbes (Post, Feb. 12)

The transcript follows.

____________________

Olney, Md.: Are there any possible ways to use bacteria to combat global warming? Such as by consuming the greenhouse gases in the atmosphere?

Rob Stein: There have been proposals to create algae blooms in the ocean to try to use those microorganisms to reduce CO2 levels in the atmosphere, but many scientists discount that as a realistic was to fight global warming.

_______________________

Fredericksburg, Va.: This article seems to suggest that the overuse of antibacterial personal cleaning products is detrimental. How should you balance between regular good cleanup and the proliferation of antibacterial products in all public spaces?

Rob Stein: Some researchers suspect that overuse of antibacterial personal cleaning products may be detrimental. This study did not directly address that question. But the researchers hope that studies like this will help them better understand the role of microorganisms in human health.

_______________________

Springfield, Va.: Do you think this study will do anything to calm all the germ/bacteria hysteria that seems prevalent today? Everyone and everything seem obsessed with killing 99.9 percent of germs and bacteria.

Rob Stein: At least some of the microbes on and in our body do perform useful roles. Bacteria in our digestive systems, for example, clearly help break down food. The researchers conducting these studies hope that they can better delineate which microbes are helpful and which are potentially harmful. That way they hope to determine whether any of our hygiene efforts have been detrimental in some way.

_______________________

Albuquerque, N.M.: Don't you think that we destroy friendly organisms and just create bigger and deadlier organisms that we don't have new drugs to combat them? I am a nurse and have been since 1962. I've seen a lot of changes and some not for the better.

Rob Stein: Yes, there's been a lot of concern in recent years about the growing problem of antibiotic resistance, which is occurring at least in part because of the overuse of antibiotics.

_______________________

Charlotte, N.C.: I am trying to understand in detail how all this invisible stuff works so that I can better take care of my skin. (1) Are there both "good" and "bad" bacteria that should or should not be on our skin, and what are the names of each? (2) What maintenance of the skin would keep it in its perfect state? Thanks.

Rob Stein: In general, the bacteria on the skin are mostly good. But in certain contexts can become bad. For example, the organisms can cause infections in someone who has an IV catheter, or if there is a wound. We don't have to do too much to have healthy skin--mostly leave it alone.

_______________________

Birmingham Ala.: In the 1960s a paperback came out with the title "Life on Man". It grossed out many of my fellow graduate students, but the little kids loved it. He talked about the bacteria, viruses, fungi, ferocious looking mites, and many other creatures.

I am glad that you are starting to catalogue the bacteria. I remember that my father was taught at George Washington University that you could wash yourself too clean, that many of the denizens living on our skin were essential to the immune system. It shall be interesting if the ecology of the skin turns out to be as important as for the digestive system.

If it is correct that the skin is the largest of the body's organs and that it produces a great many essential compounds, then what would be the effect of an unhealthy skin on the body's health--beyond the obvious effects of infection? Would a sick ecosystem on the skin result in a decreased production of important compounds?

Rob Stein: People with skin diseases can develop systemic illnesses but these are uncommon. Many skin problems are mostly of cosmetic significance.

_______________________

Hanover, Pa.: Hi. I know that penicillinase is a major, growing problem with treatment of bacterial pathogens. Do you know if there is any research into developing a compound that will block, or render penicillinase ineffective. It seems to me that such a drug, if safe could be compounded with the penicillin itself. Thank you.

Rob Stein: Penicillinase inhibitors have been developed and are in use today.

_______________________

Alexandria, Va.: If only 10 percent of cells on our body are human cells, doesn't that make us just one big microorganism?

Rob Stein: That's exactly why some researchers believe it is very important that we learn more about these organisms. Since there are so many of them, they may be affecting our biology in profound ways.

_______________________

Washington, D.C.: Great article today. Thanks! I was curious: The researchers reported finding an average of 50 different species on a small patch of each test subject's arm. Are there any figures related to how many individual bacteria were found? I've seen figures as high as 32 million bacteria per square inch of skin, and wondered what the latest studies have determined. Would 32 million/square inch be in the ballpark? Thanks.

Rob Stein: Unfortunately, the researchers didn't quantify the bacteria that way.

_______________________

Arlington, Va.: Did the six people have different washing habits? How does using anti-bacterial soap affect any "good" bacteria, or the balance of good and bad bacteria on our skin?

Rob Stein: The researchers studied bacteria on the middle of the forearm precisely because it's not washed as much as the hands.

_______________________

skin: Do people from different climates have different populations of bacteria?

Rob Stein: Probably. The researchers found a lot of variation in the subjects they studied from the same location.

_______________________

Harrisburg, Pa.: What happens to this bacteria what a person dies?

Rob Stein: The bacteria, like the rest of us, goes into the soil.

_______________________

Little Rock, Ark.: There seems to be enormous lack of knowledge about skin disinfection, particularly hazardous in the face of pandemics. Traditionally, disinfectants were judged on their phenol coefficient, that is by comparing the material to phenol in its ability to kill microorganisms. This was a rational system with numerical results, but by now, any mention of phenol (aka carbolic acid) is sure to be politically incorrect. Instead there is an intensive commercial campaign to sell products of dubious effectiveness. Some examples, triclosan containing soaps and detergents, 60 percent alcohol hand washes, other alcohol containing products, and "quats" quaternarary ammonium

All of these fail in application. The two simplest hand or skin disinfectants that are universally cheaper than advertised brands are: povidine products (eg Betadine) and Clorox in a 5 percent dilution. Either may be disguised by perfumes, are readily available without prescription and are far more effective against all manner of microbes, fungi, or things a three year old can find digging in dirt. Spurious claims that a product will kill 98 percent of germs ignore the fecundity of microbial life. But what does Rob Stein have to say about these pressing matters?

- Cecil H. Fox, Ph. D.

Rob Stein: That all sounds about right to me...

_______________________

Naples, Fla.: Very interesting article, thanks. Where was this research published? I would like to take a look at their data. Thanks again..

Rob Stein: It was published online last week by the Proceedings of the National Academy of Sciences (PNAS.ORG)

_______________________

Van Ness, DC: So, would animals have human microbes on their skin?

Rob Stein: Absolutely.

_______________________

Alexandria, Va.: Hi, To answer one of your questioners, I believe that the idea of stimulating phytoplankton growth in the open ocean (with iron supplements) was tried, but it didn't work well. The idea was based on the fact that algal growth is iron-limited. But maybe there are other limits on algal growth in the ocean that aren't yet understood.

Regarding the skin microbes, I understand that the investigators took forearm skin as their terrain for the study. Considering that the underarm and genital areas are moister, is there any indication if those areas are more diverse, or the same? Also, considering that probiotics can be used to modify the composition of the gut flora, it it possible that the skin flora could be modified with beneficial results?

Rob Stein: The assumption is that other areas of the body, such as the armpit, scalp and groin, do probably have even more diverse populations of bacteria (as well as other organisms, such as fungi).

_______________________

MoCo MD: Anything new on MRSA?

Rob Stein: This study, obviously, did not look at the MRSA issue. MRSA stands for Methicillin Resistant Staphylococcus Aureus, which is an infection that had once been found almost exclusively among very sick patients in the hospital. In recent years, it has been found more commonly outside the hospital setting, which is causing alarm among public health experts.

_______________________

V-day: Ewww, then what's on our lips when we kiss?

Rob Stein: Well, bacteria, and probably LOTS of them! That's the bad news. The good news is that they're largely friendly little critters...

_______________________

Harrisburg, Pa.: When we die and are buried, does the bacteria continue living on the decaying body and does it die at a certain point of decomposition, or does the bacteria find another home separate from the body within the soil?

Rob Stein: It probably just goes into the ground and finds another place to live.

_______________________

critters: What about other critters like eyelash mites, were they counted?

Rob Stein: Not for this study study -- they focused exclusively on bacteria. They doing separate research on other microorganisms, such as fungi, and finding similar things.

_______________________

Burke, Va.: The more we look at out world the more interesting it gets. I think if we really spent some time on the question of bacteria that grow on our skin and their relationships we'd enter a world more wonderful an any we imagined.

Rob Stein: The researchers conducting this work obviously feel that way, and suspect there's a lot more interaction between our own genes and these microbial genes than anyone realizes.

_______________________

baby: Would babies likely have as many diverse bacteria populations?

Rob Stein: probably not initially. but there is some evidence that children eventually have very similar microbial populations to their mothers.

_______________________

Burbank, Calif.: How did the bacteria get on the skin? Are they produced by the body, or were the organisms merely stowaways from the outside environment?

Rob Stein: They are not produced by the body. We pick them up from the environment.

_______________________

Rob Stein: Thanks everyone for lots of great questions!

_______________________

Editor's Note: washingtonpost.com moderators retain editorial control over Live Online discussions and choose the most relevant questions for guests and hosts; guests and hosts can decline to answer questions. washingtonpost.com is not responsible for any content posted by third parties.