Bacteria tests reveal how MRSA strain can kill in 24 hours

The Guardian (UK) ^ | 1/19/07 | Ian Sample

[kiriath_jearim]

Scientists have unravelled the workings of a deadly superbug that attacks healthy young people and can kill within 24 hours.

PVL-producing MRSA, a highly-virulent strain of the drug-resistant superbug, methicillin-resistant staphylococcus aureus, has spread around the world and caused deaths in the UK, Europe, the US and Australia. PVL or panton-valentine leukocidin toxin destroys white blood cells and usually causes boils and other skin complaints. But if it infects open wounds it can cause necrotising pneumonia, a disease that rapidly destroys lung tissue and is lethal in 75% of cases.

Thousands of infections have been recorded across the US, but scientists believe the number is likely to rise in Britain.

In 2004 the bug claimed the life of Richard Campbell-Smith, a fit 18-year-old Royal Marine, who died three days after scratching his legs on gorse during a training exercise in Devon. In December an outbreak at Norfolk and Norwich University hospital killed a baby and infected five others. According to the Health Protection Agency there were 106 cases of PVL-MRSA in England and Wales in 2005 and one confirmed death from necrotising pneumonia caused by the infection.

Scientists at the University of Texas in Houston and Lyon University in France conducted experiments into PVL to work out why it was so lethal. They took two batches of normal staphylococcus aureus bacteria and modified one of them to produce the PVL toxin.

The researchers exposed mice to the different groups of bacteria, to see if they developed lung infections. Animals that inhaled the normal staphylococcus were unaffected, but those that inhaled the PVL-producing staphylococcus quickly developed necrotising pneumonia, with some dying within 48 hours.

[srmorton]

I think you meant to say that it was highly sensitive to methicillin, as are most strains of Staphylococcus aureus.

[iwannabeme]

I do research on this bug and I thought I could explain that the 75% mortality rate was referring to the specific syndrome of necrotizing pneumonia. Most Community acquired MRSA cases are skin and soft tissue infection like boils, pimples and abscesses. But sometimes the bug gets to the lungs and causes a bloody pneumonia that seriously destroys lung tissue, called necrotizing pneumonia. I know doctors who have seen kids die of this in a matter of 24-48 hrs after coming to the Emergency room for treatment. THis syndrome causes 75% mortality. The skin and soft tissue infections are often treatable, if the doctors realize what they are dealing with. Hope thsi helps.

[iwannabeme]

VRSA is scary. However, I wanted to point out that the community-acquired MRSA strains are unlike the hospital acquired MRSA in that the community strains are actually susceptible to many antimicrobials besides methicillin. This is the silver lining about community acquird MRSA but in some locations such as TAiwan, where antibitoics are available over the counter, even the community strains are resistant to mostly everything. The VRSA that have been described so far are also resistant to many things so that is scary.

[blinachka]

You're right! My bad - the Staph I carry as "normal flora" is highly susceptible to Methicillin! Thanks for pointing out my error!

[najida]

In nursing homes and LTC, it's becoming more and more common.

[Fitzcarraldo]

You've forgotten the keystone of it all, global warming.

Or, more generally, unapproved global climate change.

[skippermd]

There is no concrete, randomized, and repeated trials on this yet, but I'm a med student and I carry a type of hand sanitizer (melaleuca brand) that has ethyl alcohol and tea tree oil in it... I use it after every patient and I use tea tree oil body wash when I get home. I also use tea tree oil mouth spray. This is all because several studies have shown that tea tree oil can wipe out mrsa colonies. Here's a link: Again, no concrete evidence, but at the hospital we are all randomly swabbed for MRSA and I have never come up positive since I started using it. Its worth the $5 a month for me. this is the website I buy from: but you can find tea tree oil anywhere-- just mix it with your purell.

[skippermd]

Sorry, I'm html challenged. Here's the link:

"http://www.rcpath.org/index.asp?PageID=798"

[mutley]

Bacterial assassin at large.

[skippermd]

Try this:

"http://www.rcpath.org/index.asp?PageID=798"

"http://www.findarticles.com/p/articles/mi_g2603/is_0001/ai_2603000122"

"www.melaleuca.com"

"http://www.biomedcentral.com/1471-2482/1/1" this article is for the more science-oriented

[skippermd]

biomed article

[blam]

"This is a serious health problem. People who stay in the hospital for any length of time are especially vulnerable, no matter what age. I was talking to a health care professional this week and I thought she said that 1/4 of the hospital patients are getting MRSA."

I asked a doctor friend of mine what he thought of the bird flu threat and he said that MRSA would kill us all before bird flu got here.

[Radix]

"I was talking to a health care professional this week and I thought she said that 1/4 of the hospital patients are getting MRSA."

That is probably an overstatement.

Hospital acquired pneumonia is a serious problem though. I read that 40% of patients who contract nosocomial infections do expire. I can not confirm that, because I only got it secondhand.

The real problems are with ventilator patients. The hospitals call it VAP (Ventilator Associated Pneumonia)and it is a serious concern all around the country.

There have been outbreaks among NFL players as well in recent years, but I don't recall reading much about that in the sports pages.

[VOA]

Someone else explained "gorse".

And it's not unknown for someone to die of an infection acquired by
having their skin punctured/abraded by plant material.

I can't recall the name of the series, but PBS had a good series on
the advancements in public health that we take for granted (in the 1900s).

One notable case occurred when penicillin was just being produced during
WWII, it was tested on a British firefighter that got a gash
(IIRC) on his face that became infected.

There was enough purified penicillin to inject the firefighter,
but it was only sufficient to halt the infection for a short time
(couple of days?).
Unfortunately, there wasn't enough penicillin available to give a
second injection.
The firefighter proved penicillin worked in humans...but he died when
the infection rallied and killed him.
Sadly, if he'd been wounded a few years later...he'd almost surely
have gotten plenty of penicillin and lived.

[NotJustAnotherPrettyFace]

Ping/bump for later reference.

[Centurion2000]

It's coming.

[saleman]

I had an MRSA infection. For some reason it's very prevalent in this area. An acquaintance got the necrotizing pneumonia. Mine started out as what looked like a spider bite. My dad's a pediatrician and recognized it when he saw it. I had it drained in his office. NOT a pleasant experience. He put me on antibiotics for a week. Should have been two cause it came back. This time I went to a surgeon and he drained it AGAIN.

Just so you'll know, when they "deaden" the site the stuff doesn't work very well cause of the acidity of the infection, I'm told.

[oh8eleven]

LOL...

[edsheppa]

You've forgotten the keystone of it all, global warming.

I thought it was the Trilateral Commission. I just can't keep up.

[Myrddin]

My dad headed to the hospital on Saturday after Thanksgiving in 2003. The doctors were escalating attempts to keep him oxygenated. A "hose on the nose", followed by a CPAP. By Sunday he was intubated. Tuesday the tube became "clogged" and he went without oxygen until his heart stopped. The doctors spent twenty minutes getting his heart running again. I called the hospital daily. By the week of Dec 17, the nurse informed me that they had hung a bag of Vancomycin to try to stop what they thought was an infection. That's pretty much the last resort. Everything was falling apart by Dec 17th. My mom and sister gave permission to turn off the respirator.

During the course of that treatment we learned a great deal about my dad's medical history that he had never shared. In retrospect, it appears he had Alzheimer's. The acute lung problems that killed him probably avoided years of unpleasant descent into a more serious expression of the disease. He was already shuffling, forgetting people, forgetting objects and becoming mean and irrational for no apparent reason.