Universal decolonization for the win against MRSA

MRSA (methicillin-resistant Staphylococcus aureus) is a huge problem in hospitals. That’s because once the usually benign bacteria establish an infection, they are nearly impossible to kill. They are resistant to almost all modern antibiotics. Ordinarily, our immune systems can handle the bugs (they aren’t more virulent than nonresistant Staph). Unfortunately, that isn’t always the case for hospital patients, who not only may be more immunologically vulnerable, but often offer easy access through open wounds or medical ports.

In an attempt to prevent MRSA from spreading in hospitals, health care workers have largely relied on two different methods. The first strategy was to screen specifically for MRSA, and then isolate and aggressively treat patients who test positive for the infection. The second is not to test for MRSA at all, but to follow universal decontamination procedures with every patient. 

In a large study published in the New England Journal of Medicine, these two techniques went head to head. Universal decolonization (removing all bacterial colonies) was the hand’s down winner, reducing all bloodstream infections, including those caused by MRSA, by 44%.

To achieve those results, patients had their nostrils swabbed twice a day with mupirocin antibiotic gel and were wiped down with chlorhexidine-impregnated antiseptic cloths. Hospital staff practiced standard contact precautions. 

One possible reason for the success of this method is the very fact that health care workers don’t have to wait for the results of tests before implementing treatment strategies. Everyone is wiped and swabbed, and as a result, the infection rate plummets.

I should point out that the doctors aren’t (yet) advocating that every person who enters a hospital submit to a full body strip and wipe down. All the procedures were done only on patients admitted to their hospital's intensive care units. I wouldn’t be totally shocked if that were to change, though.

More on this from Maryn McKenna at Wired Science.

Image: 2005 scanning electron micrograph (SEM) depicted numerous clumps of methicillin-resistant Staphylococcus aureus bacteria, commonly referred to by the acronym, MRSA; Magnified 9560x.

Huang, S., Septimus, E., Kleinman, K., Moody, J., Hickok, J., Avery, T., Lankiewicz, J., Gombosev, A., Terpstra, L., Hartford, F., Hayden, M., Jernigan, J., Weinstein, R., Fraser, V., Haffenreffer, K., Cui, E., Kaganov, R., Lolans, K., Perlin, J., & Platt, R. (2013). Targeted versus Universal Decolonization to Prevent ICU Infection New England Journal of Medicine DOI: 10.1056/NEJMoa1207290.

Solving race problems with a rubber hand

Lara Maister and Manos Tsakiris of the University of London, and Natalie Sebanz and Günther Knoblich of Central European University have a novel approach to combatting racism. They give people the rubber hand illusion treatment.

One of the reasons that racism is so difficult to eradicate is that many people genuinely feel less empathy for members of other races. The insidious thing is that they may not even be aware that they feel this way. 

If they don't know they have these feelings, then how do we know they do? One way is by using Implicit Association Tests (IAT). These tests ask people to sort words or images into groups as quickly as they can. For example, a volunteer might have to decide whether to put a lemon in the ‘good’ or ‘bad’ category. People are much quicker at sorting things in a way that makes sense to them. A racist might put a dark-skinned face in the ‘good’ column for the benefit of observers, but he’ll be a lot slower about it than a person who really believes dark-skinned people are good. 

Sure enough, even people who don't consider themselves bigoted and who make every effort to act and speak in unbiased ways often display inherent prejudices when subjected to these kinds of tests.

This sounds like really bad news for combatting racial prejudice and misunderstanding. However, Lara Maister and her colleagues have some good news for us. It turns out you can make people more sensitive to the plight of outgroups, and all it takes is a rubber hand. Or more specifically, the rubber hand illusion.

First, what is the rubber hand illusion? Watch this clip to find out.

The interesting twist is that the researchers gave light-skinned Caucasians dark-skinned rubber hands.

Before the experiment, the light-skinned participants were given IATs to measure their unconscious attitudes toward dark-skinned people. Once this baseline level of racism was established, the participants were treated to the rubber hand illusion with a dark-skinned rubber hand. Immediately afterward, they were asked to rate how much the rubber hand had seemed like a part of their own bodies. Finally, the volunteers repeated the IAT.

People who felt the illusion of ownership of the dark rubber hand more strongly also became implicitly more positive toward dark-skinned people. Apparently, people subconsciously think, ‘hey, if I’m part black myself, they can’t be that bad.’

This doesn’t surprise me. Anything that makes the ‘other’ more familiar is going to reduce fear and animosity. I’m not sure whether this information will prove to be that useful though. For one thing, we can’t require that citizens undergo rubber hand treatment, and even if we did there’s no guarantee that the effects would last. Still, it’s good to know that racial attitudes aren’t as deeply ingrained as we might think.


Maister, L., Sebanz, N., Knoblich, G., & Tsakiris, M. (2013). Experiencing ownership over a dark-skinned body reduces implicit racial bias Cognition, 128 (2), 170-178 DOI: 10.1016/j.cognition.2013.04.002.

Just for fun: Extra!

I published my Friday post yesterday, so you guys get an extra 'Just for fun' this week. It's usually only the Facebook fans who get extra videos! 

Here's a classic by Minute Physics.  Enjoy. 

Human genes can't be patented? Not so fast

Normally, I only post one story a day, but I just couldn’t wait until tomorrow for this!

Today, the Supreme Court ruled that human genes cannot be patented! Yeah! Except, they didn’t really rule that way, because the decision included this paragraph:

...but the lab technician unquestionably creates something new when cDNA is made. cDNA retains the naturally occurring exons of DNA, but it is distinct from the DNA from which it was derived. As a result, cDNA is not a “product of nature” and is patent eligible under §101, except insofar as very short series of DNA may have no intervening introns to remove when creating cDNA. In that situation, a short strand of cDNA may be indistinguishable from natural DNA.

Let me translate. 

A gene, as it exists as part of of your chromosome, contains both coding parts, which are called ‘exons’, and non-coding parts, which are called ‘introns’.  After being transcribed into RNA, the non-coding bits are removed to make mature mRNA. You can see that in the diagram below. 

The mRNA is then translated into a protein. Although this doesn’t ordinarily happen in mammalian cells, a geneticist can take that mRNA and reverse transcribe it back into DNA. This is called ‘complementary DNA’, or cDNA, and it's identical to the original gene, except without the introns. 

Thus, the court ruling says that if I chop a piece of DNA out of your chromosome, I can’t patent it. But if I make cDNA from your gene (and remember, the cDNA has all the coding parts from which I can make the original protein), then I can patent that*.  

And that’s different from patenting human genes how?

*It's been pointed out to me by David Pacheco that the Supreme Court did not specifically rule on whether cDNA is patentable, it just didn't say cDNA definitely could not be patented, as it did with naturally occurring DNA. In other words, the Court's decision may be more nuanced than I've given them credit for. Nonetheless, the ruling is far from a ban on patenting human genes as many of the headlines would have you believe.

New and improved surgical biopsies

When doctors are trying to figure out what’s wrong with you, they’ll often want to take a biopsy of the affected area. This usually means inserting a pair of biopsy forceps and pinching off a piece of your flesh. You can see an example of such a device below, courtesy of Device Technologies. 

If it makes you squeamish, note that the jaws of such tools are only a couple of millimeters long. That’s not tiny enough for the researchers at Johns Hopkins, however, who have manufactured and tested autonomous microgrippers that are ten times smaller.

This image depicts an mu-gripper near the opening of an endoscopic catheter. 
Credit: Evin Gultepe, Gracias Lab, Johns Hopkins University.

The minute star-shaped objects are composed of temperature-sensitive metals that squeeze closed when they are exposed to body temperature. Doctors can use a catheter to deploy hundreds, or even thousands, of them into a suspicious region of the body. In a few minutes, the microgrippers warm up and close around tissue samples. Because the grippers contain nickel, they can then be collected with a magnetic probe.

This is much less invasive than conventional tissue sampling for a number of reasons. First, you’re collecting much smaller samples. Second, you can deploy as many microgrippers as you need to be reasonably sure you’re getting a representative tissue sample. To get the same result, doctors might have to make tens of sequential forceps biopsies. Finally, you need far less precision and training to get the samples you want, which might make it faster and easier to perform biopsies.

So far, animal tests have been promising, though more refinements will be necessary before the doctors move on to human trials. At a minimum, I'm sure patients will want to know whether doctors can reliably retrieve every last microgripper and what the dangers are of leaving one behind.

Here's an animation explaining their usage:

Or watch one in action here:

Gultepe, E., Yamanaka, S., Laflin, K., Kadam, S., Shim, Y., Olaru, A., Limketkai, B., Khashab, M., Kalloo, A., Gracias, D., & Selaru, F. (2013). Biologic Tissue Sampling With Untethered Microgrippers Gastroenterology, 144 (4), 691-693 DOI: 10.1053/j.gastro.2013.01.066.

Just for fun: The invisible artist

Many artists claim to lose themselves in their work, but no one does it quite like Liu Bolin. Judge for yourself:


Hiding in New York No. 7 — Made in China, 2012. Photo: courtesy of Eli Klein Fine Art, © Liu Bolin

You can see more of Bolin's work here (don't miss the dragon), or watch his TED talk where he explains his origins in protest and demonstrates his technique:

Tunneling for tumbling ants

Why are ant tunnels so uniform in diameter? If you guessed for ease of movement, you'd be only partially right. Ants do need their tunnels to be accessible passageways, but there's a more important reason for building them to such exacting specifications. It seems that ants construct their tunnels of the optimal size to catch them when they fall down the shafts, something that happens a lot more often than you might suspect. Ants are surprisingly clumsy travelers.

Say what you will about fire ants (Solenopsis invicta), they’re experts at building complex underground pathways. They’re also readily available around the Georgia Institute of Technology, which is where Daniel Goldman and his team work. 

The researchers collected the ants and provided them with soils containing a variety of particle sizes and moisture contents. Regardless of the substrate, the ants constructed tunnels with the same diameter. The tunnels varied in length and direction, but were always slightly wider across than one ant length. You might think this width was selected for as the smallest size that still permits rapid movement. However that wasn't the case. 

In a rather surprising discovery, the scientists found that ants use their antennae to catch themselves as they tumble down vertical tunnels. This suggests that tunnel diameters may be optimized not so much for rapid deployment as for letting ants recover from slips. 

If you want to see examples of an ant slipping down a tunnel, check out this video of Goldman explaining their work.

By the way, as interesting as these studies are, and who doesn’t find ants fascinating, Goldman and his colleagues have another purpose. They hope to someday be able to apply what they learn to the field of robotics. After all, ants are experts at building uniform structures out of diverse materials. As he explains:

Lots of the materials in disaster sites - landslides, rubble piles - are loose materials, which you're going to potentially have to create structures out of.

If all goes well, in future disaster zones we could have multitudes of mechanical ants or little robots that look like  cockroaches that will swarm all over the place.

Gravish, N., Monaenkova, D., Goodisman, M., & Goldman, D. (2013). Climbing, falling, and jamming during ant locomotion in confined environments Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1302428110.