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Print 25 comment(s) - last by Seemonkeyscanf.. on Jul 2 at 3:10 PM

Bacterial resistance to treatments may become a thing of the past thanks to a little green dye and low power lasers.

Bacteria can be a big problem. Bacterial infections kill many thousands of people each year, even in hospitals where care can be given. Some of these infections come from those very hospitals, in fact.

A growing problem is that bacteria, like most organisms, evolve to combat things that are dangerous to them. This has produced strains of bacteria that no longer respond to treatments that once hindered their growth. While advances such as MIT's bacteria resistant polymer will surely help prevent hospital-caused infection, it does not help treat them once they've taken root, nor can it do much against infections caused from accidents in less clean environments.

That's where lasers come in to diffuse the situation. While the statement conjures up visions similar to Johns Hopkins's virus busting laser, raining beams of bacterial genocide down upon an infection, it's a lot less difficult than that. In fact, the laser in this case doesn't even need to make contact with the bacteria to do the job. Instead, a harmless dye known as indocyanine green is what brings a quick end to the harmful invaders. Or more specifically, what happens to the dye when it's activated by a near-infrared laser.

The effect is similar to Rensselaer Polytechnic Institute's cancer killing nanoparticle treatment. When a laser, in this case a 500mW gallium-aluminum-arsenide near-infrared laser projecting at 808nm wavelength, is shined at a photosensitizer, the indocyanine green, it creates free radicals known as reactive oxygen species. These free radicals destroy bacteria by disrupting numerous parts of their physiology.

One benefit to this method is that it is very unlikely a strain of bacteria could develop a resistance to this type of treatment. Too many parts of the bacteria are affected simultaneously. Bacteria develop resistance to antibiotics by changing whatever part of their anatomy that the antibiotic affects, evolving to counteract it much the same way insects evolve to live undaunted by pesticides used to treat farm crops.

Another positive quality of this treatment involves the penetration properties of the near-infrared laser. While the duration and power do not cause temperature fluctuations like more powerful infrared lasers, the wavelength allows the wave to pass through a limited amount of flesh, reaching subcutaneous areas, allowing non surface bacteria to be destroyed as well, provided the dye can be absorbed into the area.

The University College of London team that developed the technology has used the technique to successfully destroy at least three different strains of bacteria: Gram-negative Pseudomonas aeruginosa, the most common type of burn infection; Gram-positive Staphylococcus aureus; and Streptococcus pyogenes.

An abstract of their findings can be found at Biomed Central, along with an unformatted PDF titled “Lethal photosensitization of wound-associated microbes using indocyanine green and near-infrared light” which explains the process and results in depth.



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Warning for the future....
By Seemonkeyscanfly on 7/1/2008 11:25:19 AM , Rating: 5
bacteria seems smart, crafty. They always take what we send in to kill them with and make themselves stronger, better, more deadly. So if we used past experiences to judge the future....I think the use of laser could promote growth of laser technology among bacteria. Once they have their own laser we'd be in deep dung – which I believe is a favorable place for bacteria..... :)

really I'm for any use of lasers....this sounds like a great step forward.




RE: Warning for the future....
By KaiserCSS on 7/1/2008 11:32:02 AM , Rating: 3
All I want is some frickin' bacteria with frickin' laser beams attached to their frickin' heads!


RE: Warning for the future....
By Seemonkeyscanfly on 7/1/2008 11:42:40 AM , Rating: 2
I walked right into that one....should have known that would have happend... :) By the way, I never knew bacteria had heads.


RE: Warning for the future....
By BladeVenom on 7/1/2008 3:30:33 PM , Rating: 2
Chuck Norris...


RE: Warning for the future....
By paydirt on 7/2/2008 9:38:01 AM , Rating: 2
"we're in deep doo now"


RE: Warning for the future....
By CloudFire on 7/1/2008 12:13:58 PM , Rating: 2
i'd say, if laser doesn't work, we should have nano-robots injected into our systems which will physically cut up the bacteria/viruses, nothing can stand sharp claws of the nano-bots!


By Seemonkeyscanfly on 7/1/2008 12:20:26 PM , Rating: 2
Namo-robots with laser on their heads.


RE: Warning for the future....
By MrBlastman on 7/1/2008 12:26:21 PM , Rating: 3
All beware the brown laser.

I hear it really stinks. :(


RE: Warning for the future....
By fri2219 on 7/1/2008 12:51:36 PM , Rating: 2
Nope, that's Lamarckianism... Giraffes don't evolve longer necks to reach the best leaves, the ones with longer necks have more offspring because they're eating better.

Bacteria multiply like crazy, resulting in a wide variety of genetic variation within a species (a term that makes zero sense for a bacterium, but I digress). The ones that don't have a way to deal with the new environment get whacked when something new pops up, and the survivors go on to found the new population.


RE: Warning for the future....
By Seemonkeyscanfly on 7/1/2008 1:47:00 PM , Rating: 2
yep, that's the logical and correct answer...but I like my story better. It will make for a better movie.
“Attack of the killer bacteria with lasers on their head....this time it's personal” :)


RE: Warning for the future....
By MrBlastman on 7/1/2008 1:49:45 PM , Rating: 2
Don't forget the sound effects.

pew pew pew pew pew pew!


RE: Warning for the future....
By paulpod on 7/1/2008 7:18:50 PM , Rating: 2
Actually it is now believed that long necks in Giraffes was the result of sexual selection. Namely that when females started selecting mates based on the neck fights you now see between males, it was off-to-the-races on neck length. Sexual selection produces the most rapid and bizarre adaptations.

If reaching for food caused long necks you would see that in a lot more animal types, present and extinct. You would also see humans from large families with 8 ft. arms.


RE: Warning for the future....
By pnyffeler on 7/1/2008 1:51:01 PM , Rating: 2
You're right to be wary of this information. The investigators left one big thing out: it would destroy your body's cells right along with the bacteria. In the tests described in the scientific paper, the system worked really well at killing bacteria when only bacteria were in the petri dish. There was no control conducted to show that human cells would also survive, which they most certainly would not. The photochemical reaction involved creates incredibly reactive & destructive chemicals that tear apart almost anything it comes into contact with.

On an interesting note, the antibiotic system is EXACTLY the same as what your own immune system uses to fight off foreign invaders like bacteria. Antibodies have the inherent ability to create the same type of reacting chemicals, but do so without the need for light (by strictly chemical reactions). Again, this would normally destroy everything around it. However, evolution created an incredibly smart system. The chemicals are so reactive that they destroy anything they touch. The immune system only allows the reactions to occur at the specific site of infection. The antibodies are all stuck to the surface of the bacteria (because they recognize it as being foreign), and as the antibodies make the reactive chemicals, the first thing they come into contact with is the bacteria. Thus, you get a targeted warhead-like effect, where the bacteria get annihilated before you get significant damage to surrounding tissue.

I did part of my Ph.D. research on this stuff. I'd bet real money that the idea for this project came directly out of the discovery that antibodies do the same reactions in the dark. The scientists just realized they could do the same thing in the light, but forgot to mention the fact that this would cause SERIOUS tissue damage if ever used in people.


RE: Warning for the future....
By ddopson on 7/1/2008 5:11:25 PM , Rating: 2
Yes, I was waiting for that. Seems like a pretty big oversight in the write-up. It's pretty easy to kill bacteria. It's really hard to do it selectively and leave other life-forms intact. Heck you could just bake the wound in an 800 degC kiln and presto, bacteria are dead.


RE: Warning for the future....
By Beefmeister on 7/2/2008 12:56:50 AM , Rating: 3
Strong beams of radiation used to treat cancer are fairly dangerous as well. But in a clinical setting you fire the beam from multiple directions to focus the exposure on small areas, and leave surrounding tissue relatively intact.

I imagine this laser system could do the exact same thing, to focus on specific sites of infection.


RE: Warning for the future....
By JonnyDough on 7/2/2008 6:22:41 AM , Rating: 2
I think you're both wrong. It would seem that the dye they used could just as well be something else, perhaps something the bacteria like to eat, or a protein they have. If you can dye a specific part of the bacteria using a special dye, then the problem is solved. What they demonstrated was not frying bacteria with a laser, what they demonstrated is a very low level laser targeting a dye that was inside of the bacteria. The end result is that the bacteria died, with very little laser light.

Think of it this way...they just gave the bacteria fatal sunburn, but only on the region they were wearing sunblock.


RE: Warning for the future....
By tmouse on 7/2/2008 9:17:21 AM , Rating: 2
No its not, as a matter of fact it has seen use in cancer trials.


RE: Warning for the future....
By tmouse on 7/2/2008 9:24:33 AM , Rating: 2
No its not, as a matter of fact it has seen use in cancer trials. Their approach is also not novel, other compounds have been tested with laser activation against microbial infections. I like the idea of less traditional methods of publication; unfortunately I see a lot of "weaker" papers getting published in them. The unfortunate mindset is "if we cannot publish in a "real" journal lets put it in an e-journal. Some have better peer review than others, right now it’s a scramble to fill them so I fear many will become dumping grounds.


By Seemonkeyscanfly on 7/2/2008 3:10:24 PM , Rating: 2
quote: "Strong beams of radiation used to treat cancer are fairly dangerous as well. But in a clinical setting you fire the beam from multiple directions to focus the exposure on small areas, and leave surrounding tissue relatively intact."

Why does the image of the Death Star come to mind? However, now it's on the light side.


RE: Warning for the future....
By FITCamaro on 7/1/2008 4:08:06 PM , Rating: 2
Yeah we gotta be careful or they'll gain the ability to attack the Enterprise. For those who remember that original series episode where an amoeba is the horrible space monster that attacks the Enterprise.


Just shove it down my throat
By Believer on 7/1/2008 11:25:22 AM , Rating: 3
Sounds like fun, next time someone get a Streptococcus infection in their throat (aka pharyngitis or "strep throat") I'll ask to shove that green thing down their mouths and beam them with 'ze lazors' till they get all better... nothing like some healthy free radicals going down the ol' pipe. :D

I love the future!




RE: Just shove it down my throat
By TheDoc9 on 7/1/2008 11:35:37 AM , Rating: 2
That's the question, are these free radicals harmful to humans as well? If not this looks like it could be a great advance, but it would suck if you got rid of your bacteria only to be in the hospital a year later with cancer.


Revolutionary
By oTAL on 7/1/2008 1:24:41 PM , Rating: 2
If we could somehow engineer minuscule sharks, attach the lasers to their heads, and inject them into the human blood stream... we could potentially get rid of all kinds of bacterial infections and diseases.

On a serious note I like this tech and it looks solid, but the Johns Hopkins's virus busting laser mentioned in the article sounds too good to be true... I'll only believe it when I hear that other people replicated the experiment throughout the world. The concept is nothing but new and has been deemed impossible several times before. Similar "technologies" were occasionally mentioned in crappy "alternative medicine" mediums, in order to steal a buck from the desperate.

Anybody has insight into that piece of technology?




RE: Revolutionary
By FreeTard on 7/1/2008 4:43:28 PM , Rating: 3
Is there any chance that the laser could then be hooked up to ADC and piped through speakers? Can it read my pores? If so will I get sued by the RIAA if my pores play a Metallica song, I don't own a copy of?

I mean technically, by having skin, I am making available.


By fri2219 on 7/1/2008 12:58:51 PM , Rating: 2
The same approach was used back in the "Magic Bullet" days of the German chemists who studied dyes in the late 1800's, just before the advent of Sulfa drugs- a cup of coffee at Engulf and Devour Espresso says that the bacteria just make an extra slime layer which excludes the dye within 6 months of widespread clinical use.

As others have mentioned, given that light needs to penetrate into tissue to activate the dye, it can only be used in places where antibiotic resistance isn't a problem. For that sort of application, there are plenty of good, cheap, "nuclear option", "old-school", topical chemotherapeutics like Bacitracin that work just fine without any resistance problems.

If they'd come up with a way to replace Clindamycin or Vancoumycin, that would be something to celebrate.

http://www.amazon.com/Elusive-Magic-Bullet-Search-...




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