Prions cling to surgical equipment

[n2doc]

Sterilisation 'may not kill CJD'

A survey has found that surgical instruments still have the potential to harbour CJD even after sterilisation. Edinburgh University found every instrument they tested was contaminated with enough protein residue to pose a potential infection risk. The researchers tested instruments taken at random from five NHS hospital trust sterile service departments. The study, financed by the Department of Health, appears in the Journal of Hospital Infection.


CJD, a degenerative and fatal brain disease, is thought to be caused by mutated proteins called prions. These twisted proteins are known to be able to cling to the surface of surgical instruments, and are remarkably difficult to remove by standard decontamination processes, which involve the use of detergents and super-heating. There have been instances of patients contracting CJD from contaminated instruments during surgery. The Edinburgh team found an average level of protein contamination of 0.2 microgrammes per square millimetre of instrument.

If prions were found on so-called sterile instruments in the levels recorded in the study, that would be billions of times the dose needed to cause infection in humans. The highest doses were found on instruments used to remove tonsils - one of the tissues known to harbour prions. Lead researcher Professor Bob Baxter, from the University's chemistry department, said "You can never get something 100% clean, but we were surprised at how much protein there was." Professor Baxter said measures to quarantine surgical instruments were taken if a patient was known to be at high risk of carrying CJD. But he said that as a result of the use of contaminated blood supplies, an unknown number of people could be harbouring the disease. "There are certainly people out there who are at risk, but we don't necessarily know who they are," he said.

The Edinburgh team has developed a more effective way to sterilise instruments, using a technique called gas plasma sterilisation. This uses radio waves to excite the molecules of harmless gases, creating charged atoms called ions and radicals which effectively scour the surface of the instruments, breaking down traces of biological tissue and converting them to non-toxic gases. Gas plasma sterilisation can remove prions to levels a thousand times lower than those achieved by existing methods. Professor Baxter has recommended the widespread introduction of gas plasma cleaning to the Department of Health. A Department of Health spokesperson said the study would be considered by an expert group. "Although we consider the gas plasma decontamination technique interesting, it is not currently in a form that can be used in routine decontamination of surgical instruments."

http://news.bbc.co.uk/2/hi/health/5281100.stm

[donsu]

1. this news should be spread far and wide!!!!

nt

[Mabus]

2. Doesn't this have huge implications for slaughterhouses

that have been found to have processed meat with BSE?

[elehhhhna]

3. Yes. All the way to your local butcher. My neighbor, the betst damnmed

BBQ/smoker in ALL OF TEXAS no kidding, was SHOCKED when I told him last night that cooking doesn't kill CJD prions. SHOCKED.

[Mabus]

6. I read Rhodes' book (Deadly Feasts) a few years back

so it doesn't surprise me too much.

There are actually things to be afraid of in this world rather than faux terror alerts.

[jilln]

5. I wouldn't count...

on much being done. The US has decided to test FEWER cows instead of more. And they don't really enforce the laws that are on the books right now, so don't count on legislation helping either.

[Mabus]

7. We need to get this clown and his minions out of office.

They are spending way too much time fighting windmills and not enough time on real dangers. Then there is the ignorance of the public that needs to be overcome too.

[The Deacon]

4. Back Before We Had Discovered Prions

We had a patient with (suspected) CJD scheduled for surgery. As the sterile processing department we called CDC for advice (there was nothing in the literature.) Their advice? Doctors & nurses should wear nothing of their own save underwear they would willingly give up. We should use only disposable instruments where possible. After surgery all clothing, including the underwear & surgical scrubs, should be removed in a curtained off area in the operating room & personnel should then exit into the scrub room to put on gowns which had never been in the operating room. After their showers everything, gowns, towels, instruments should be transported by one person to our incinerator to be burned - and the last thing into the incinerator should be the clothing the transport person was wearing.
I was much relieved when I arrived at work that night (the surgery was scheduled for late night to minimize contact with patients & personnel not directly involved) to discover the patient had taken a turn for the worse & the surgery was canceled - two guesses who the "designated transport person" was. (Sterile processing is one of the few professions where seniority gets you the nasty little jobs rather than getting you out of the nasty little jobs.)

[cascadiance]

8. For many not studying this, mutated prions is what Mad Cow disease is...

All the more reason why we in the U.S. and Canada need to get in line with the Europeans and Japanese in their stricter rules to prevent the spread of Mad Cow disease. This means not just preventing cattle parts from being used in cattle feed (which was the main source of it being spread before that is already instituted), but also preventing cattle remains from being used in feed to poultry and pigs, which though don't "get" this disease, have been found to be carriers. And then likewise, not to have their parts being used in cattle feed. We might be sitting on a time bomb and not know it just yet. This other means of transmission makes it potentially worse too now. Europeans and Japanese already have tighter feeding restrictions in place that will prevent this sort of transmission.

[HiFructosePronSyrup]

9. This has been known for years.

It's been known that conventional autoclaves don't destroy prions. That's why labs specializing in prions are equipped with extra heavy duty autoclaves and incinerators.

[w4rma]

10. So those blades that cut prion infested meat most likely have a coat

of prions on them? As I'm sure that there has been prion infested meat that has passed through.

[nashville_brook]

11. are prions actually "alive" ??

[htuttle]

12. IIRC, the same question can be asked of viruses

As it looks to me know, viruses and prions are both very close to the line between life and non-life. Most likely, viruses are just barely 'life', and prions are just barely 'non-life'.

[HiFructosePronSyrup]

13. Depends how you define life.

The line between what's alive and what's not probably isn't as discreet as most people would be comfortable with.

[TechBear_Seattle]

14. Only in the sense that any other protein is "alive"

Prions are essentially a single protein that has folded into an abnormal configuration. It is not a cooperative of different proteins, lipids and other molecules like a virus or cell.

The two things that make prions dangerous is that a) prions seem able to reconfigure normally folded proteins into refolding as prions and b) prions can not be used by cells, which require that proteins be folded to form very specific shapes. While a virus can take over a cell to make copies of itself, a prion can't even do that: it must run in to an otherwise identical protein and reconfigure it.

[DireStrike]

15. Wait a minute, everybody doesn't know this yet?

Even butchers?

ugh.


You can bet that the cattle industry bigshots know about this. That's why I'm done with beef. But really when you think about it, that's only a single major way to catch it, with hundreds or thousands of other means of transmission.