Posted on 11/19/2013 2:30:07 PM PST by Dysart
Around 20 percent of all humans are persistently colonized with Staphylococcus aureus bacteria, a leading cause of skin infections and one of the major sources of hospital-acquired infections, including the antibiotic-resistant strain MRSA.
University of Chicago scientists have recently discovered one of the keys to the immense success of S. aureus—the ability to hijack a primary human immune defense mechanism and use it to destroy white blood cells. The study was published Nov 15 in Science.
"These bacteria have endowed themselves with weapons to not only anticipate every immune defense, but turn these immune defenses against the host as well," said Olaf Schneewind, MD, PhD, professor and chair of the Department of Microbiology at the University of Chicago and senior author of the paper.
One of the first lines of defense in the human immune response are neutrophils, a type of white blood cell that ensnares invaders in neutrophil extracellular traps (NETs), a web-like structure of DNA and proteins. Captured bacteria are then destroyed by amoeba-like white blood cells known as macrophages. However, S. aureus infection sites are often marked by an absence of macrophages, indicating the bacteria somehow defend themselves against the immune system.
To reveal how these bacteria circumvent the human immune response, Schneewind and his team screened a series of S. aureus possessing mutations that shut down genes thought to play a role in infection.
They looked to see how these mutated bacteria behaved in live tissue, and identified two strains that were unable to avoid macrophage attack. When these mutations—to the staphylococcal nuclease (nuc) and adenosine synthase A (adsA) genes respectively—were reversed, infection sites were free of macrophages again. Looking for a mechanism of action, the researchers grew S. aureus in a laboratory dish alongside neutrophils and macrophages.
(Excerpt) Read more at medicalxpress.com ...
Interesting.
From what I’ve read, the reason so many otherwise healthy people died so quickly from the Spanish Flu is precisely this. Their immune systems went into overdrive and started attacking the flu only to overwhelm all the other systems of the body.
That would precipitate organ failure/shock.
All humans are permanently populated with bacteria, viruses, um ‘yeasts’ and protozoa of a wide variety. We are just as much a viable ecosystem for them as forests are for bunnies.
That is no surprise.
This article is “interesting” but not terribly revealing.
No. The article which you either did not read or failed to understand doesn't assert a new finding with disclosure that we harbor biological organisms.
It does reveal the mechanism of action in which staph appropriates the host's own immune system for itself by in fact targeting the host.
"Our work describes for the first time the mechanism that these bacteria use to exclude macrophages from infected sites..."
First of a kind finding, and potentially vital discovery and basis for detecting solutions to combating this deadly bug. Why attempt to critique something you've (hopefully) not taken the time to read?
Post to me or FReep mail to be on/off the Bring Out Your Dead ping list.
The purpose of the “Bring Out Your Dead” ping list (formerly the “Ebola” ping list) is very early warning of emerging pandemics, as such it has a high false positive rate.
So far the false positive rate is 100%.
At some point we may well have a high mortality pandemic, and likely as not the “Bring Out Your Dead” threads will miss the beginning entirely.
*sigh* Such is life, and death...
Dysart spin down, please. A long time ago I was deep into cell physiology. Over the years I developed a certain cynicism for ‘discoveries.’ Why? — for example, what I was taught/learned about the chemistry of wound pain was supplanted several times by new ‘discoveries’.
My reaction was indeed more about a reaction to the idea that folks might be surprised to learn that our bodies are hosts to a lot of organisms that CAN be pathogens. I quit reading Scientific American when it became a political instrument in the early 80s. So yeah, I am not as close at all to the physiology as I used to be. But I still read interesting articles
What they appear to have demonstrated above the mechanism employed by Staph A was indeed interesting. It might lead to a new way to fight MRSA, which would be a good thing.
Now WRT your comments about didn’t read or fail to understand, feel free to piss off. Lose the insulting approach - you’ll go farther.
Welcome to FR. Enjoy your day.
Perfect, old fellow. As I would expect.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.