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Any bio experts out there? ( bacterium)

TillEulenspiegel

Master Poster
T
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May 30, 2003
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Quick question .
Is there an identifiable constituent ( such as protein coat ) that MERSA and VRE are identifiable by yet?
Thnx.
 
I am not a bacterium but I play one on TV.

MRSA= Methicillin-resistant Staph Aureus

VRE= Vancomycin-resistant Enterococcus

They are different genera.

Did you mean to ask about MRSA vs VRSA (its even scarier brother), or did you mean to ask about MRSA and VRE vs the less dangerous members of their own species?
 
No I meant to ask about those specific organisms and Jesus don't even mention VRSA. (Ashes ,ashes ,all fall down!)
 
They are defined by their interaction(resistance) to a particular antibiotic, methicillin or vancomycin. Obviously there is a genetic element that is coded, but they are for most practicle intents and purpose identical (except wrt antibiotic resistance) to normal members of their species. S.aureus is part of the human bodies normal flora. Enterococci are normal gut flora.
 
So theres no specific say receptor site on the coat that would differentiate them from their less dangerous brethren? All the differences reside in the DNA only? ( I'm Way out of my field here).
 
http://www.cdc.gov/ncidod/hip/Lab/FactSheet/mrsa.htm

Staphylococcal resistance to oxacillin/methicillin occurs when an isolate carries an altered penicillin-binding protein, PBP2a, which is encoded by the mecA gene. The alteration of the penicillin-binding protein does not allow the drug to bind well to the bacterial cell, causing resistance to -lactam antimicrobial agents.
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The easiest way to detect MRSA is by antibiotic sensitivity testing!
 
Prester John said:

The easiest way to detect MRSA is by antibiotic sensitivity testing!
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Take 10 elderly orthopaedic patients. Sit them in an NHS hospital ward and culture their wounds after a week or so. What you grow will be MRSA. Easy.
 
Funny thing is - remember Jareth, the collie whose face fell off while CD was "treating" him homoeopathically? Well, when he was finally taken into the RVC, one of the first things the dermatologists suggested for why the poor dog wasn't responding to "treatment" was that he might have MRSA.

Huh?

Anybody ever yet reported an MRSA isolate in a veterinary hospital? No.

Anybody at that time reported an isolate of MRSA from a human loose in the community? I don't think so, or at least damn few.

Any special reason why this dog, who had had very little antibiotic treatment over the years, and who was living in the community with no known contact to a human case or anything, should have MRSA? No. About as likely as him having cholera I should think.

Staph aureus is a human organism. The equivalent skin organisms in dogs are Staph epidermidis (commensal and occasional opportunist) and Staph intermedius (pathogen). If we isolate Staph aureus from a dog, we can be pretty sure it got it from a human. (Probably the surgeon....) MRSA is completely unknown in veterinary medicine, even now.

Never mind, as soon as a case which isn't responding to treatment comes in, the first thing a couple of senior veterinary dermatologists theorise is that he has MRSA. Even though he's a dog, has been nowhere near a human hospital, and hasn't had much antibiotic treatment. The non-response to "treatment" couldn't possibly be anything to do with the fact that the "treatment" consisted of magic sugar pills, could it?

Sheesh, sometimes you have to wonder about your colleagues.

Normal service will now be resumed in this thread.

Rolfe.
 
Badly Shaved Monkey said:
Take 10 elderly orthopaedic patients. Sit them in an NHS hospital ward and culture their wounds after a week or so. What you grow will be MRSA. Easy.
Click to expand...

That is unfortunatly very close to the truth :(
 
Rolfe , now this is just plain scary:

"Between July and December 2000, four MRSA infections were detected in one veterinary diagnostic laboratory in southern Ontario. Case 1 was a dog with a post-operative MRSA wound infection. The isolate was identical to an MRSA identified a year earlier from her owner who had been hospitalized for surgery. Case 2 involved a dog with MRSA ear infection and concurrent inpatient orthopedic surgery, whose owners had frequent outpatient institutional contact. Case 3 was a horse with a post-operative MRSA wound infection whose owner was colonized with an identical strain. Case 4 involved a dog requiring leg amputation following an MRSA wound infection at a fracture site. The owner of the dog had previously been hospitalized for cancer. All the MRSA isolated from these animals were indistinguishable from the major human clones found in Ontario."
Article : http://www.cacmid.ca/abstracts_01/r2.htm

I'm a little acquainted to MRSA as I contracted it during a hospital stay. Treatment was 6 weeks of Vancomycin 2-weeks in hospital, 4 weeks outpatient course was (IIRC) 2G dilute in 500mL IV push via PIC line at 250mL Hr. Had peak and trough every ~4th day. I was eliminating the stuff at a ridicules rate. No red-man or kidney problems.

Reason I'm asking about methodology of detection , other then the convention of culturing, is because there are new class of SOS (sensors on silicon) that can directly measure not just gasses but VOCs and even proteins. Silicon protein detectors are "lattices" of electroststically bonded agents that react to a specific proteins make up. This is done in real time. If the PBP2a protein is accessible either directly or by a chemical or enzymatic breakdown of the bacterium , the possibility then would exist for faster detection and treatment.

Just an intellectual exercise for now.
 
Prester John said:
That is unfortunatly very close to the truth :(
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Yes, be sure to mix up post-surgical patients with ones coming in to have unidentified abcesses drained on the same over-stretched ward.
 
Till Eulenspiegl, I can't say I'm surprised. It seems so likely, it was only a matter of time. To the best of my knowledge it hasn't happened in this country yet, God alone knows why. I run a diagnostic lab for animals, and although we occasionally find Staph aureus, we've never found an MRSA yet.

I wouldn't be surprised if it happened though.

I just don't think it will happen in a dog belonging to a couple of woos who think real medicine is evil poison and all you need to heal is some sort of distance healing based on colours of the spectrum. So maybe it's not all bad being a woo. Oh yes, I forgot, the dog eventually died of an infection with a perfectly ordinary collection of organisms that were sensitive to quite a wide range of antibiotics.

Rolfe.
 
There are established protocols for the handling and treatment of MRSA patients, yet for a month, I sat in a chair next to old,infirm and immune suppressed patients with no isolation in fact there was much mutual contact either directly ( chairs touching, hand me your paper when done will ya ?, etc.) and nurses who did use gloves but only when in direct contact with blood, body fluids or instruments. ( who wants a cup of coffee?, lunch time Mr. Jones heres your tray...).
My brother owns a company that certifies labs,operating rooms, pharmacies, clean rooms and trains professionals in sterile techniques ( another reason for my interest in the subject ). He told a frightening tale about such minor (?) issues as un-sanitary behavior of Pharmacy techs that have and do cause death and injury , just because they didn't wash their hands after a bathroom break. Almost makes you paranoid.
 
When I was hospitalised with pneumonia of unknown origin, they put me in a single isolation room, and barrier nursed me. Maybe the fact that my boss had just rung the hospital and told them I worked in a veterinary lab had something to do with it?

The facilities were really good, I was told this was because the hospital was only about 5 miles from Garwick Airport. On day three the nurses started coming in without face masks, and I enquired sweetly if word had got out that I'd finally managed to clean my teeth?

Anyway, it was impressive. But this was 16 years ago.

Rolfe.
 
The spread of Common Sense Resistant Paranoia can be slowed by placing one's head under the blankets and never reading someone else's paper. Or any paper.

Rolfe- is there anything about the bacterium that would make it diffficult for it to make the generic jump? Imean, does Staph.a. KNOW it's a "human " bacterium? Anything about us it needs? Or are we just the only ones using antibiotics too much?

Because cows , sheep and chickens come to mind...
 
Soapy Sam said:
Rolfe- is there anything about the bacterium that would make it diffficult for it to make the generic jump? Imean, does Staph.a. KNOW it's a "human " bacterium? Anything about us it needs? Or are we just the only ones using antibiotics too much?
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We are not the only ones getting too much antibiotic. Vets are just as culpable as doctors. But vets don't keep so many very sick patients in hospital in high-density populations, so less resistance builds up.

Staph aureus knows it's a human bug. If you isolate it from an animal, you ask the surgeon how often he washes his hands. I've got it up from instruments and operating tables in vets' surgeries, when they've done sterility checks. The equivalent organisms on dog skin are Staph epidermidis (commensal and occasional opportunist) and Staph intermedius (pathogen). They're all quite closely related organisms, but distinct. If my memory serves me correctly, it used to be "Staph aureus var. intermedius" or something like that.

Rolfe.
 
But vets don't keep so many very sick patients in hospital in high-density populations, so less resistance builds up.


MM. I'm thinking battery farms / fish farms??? (I know they don't handle the fish much..)
 
Rolfe said:
We are not the only ones getting too much antibiotic. Vets are just as culpable as doctors. But vets don't keep so many very sick patients in hospital in high-density populations, so less resistance builds up.

Rolfe.
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Factory farming where animals are treated regularly inoculated and then consumed are evidently one of the major avenues of human ingestion of anti-biotics.

Theres a little company ( Vindicator) about 20 miles down the road from me that uses a vault with a chunk of cobalt under water open the door close the door , open the vault wait 20 secs and veee-ola!, no live contaminants. Course if you think Homeopathy brings out the nuts , say the word "Radiation" and wham you have a parade of everyone from anti-world trade groups to Lesbians from Saturn on your door step.

Edit to add: Cross species pathogen jumping is a very bad thing. HIV is theorized to have jumped by human consuption of monkey meat contamiined with Simian I-dV. Ebola also seems to have similar roots.
 
TillEulenspiegel said:
Factory farming where animals are treated regularly inoculated and then consumed are evidently one of the major avenues of human ingestion of anti-biotics.
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What do you mean by "inoculated"? Vaccinated? That's the usual implication, and that has nothing to do with the subject on the card.

As far as the use of antibiotic-medicated feeds as growth promoters goes, there are very strict regulations (at least here, your mileage may differ) regarding withdrawal times before slaughter and the meat is tested to make sure there are no residues. Humans do not ingest antibiotics by this route.

I think feeding antibiotics to cattle to improve growth rates is brain-dead, nevertheless the evidence is heavily against its actually having been much if any of a factor in the development of antibiotic resistance in organisms important in human pathology. More likely to increase resistance of the organisms bothering the cattle themselves. Except they usually use preparations that don't have major therapeutic uses.

The main cause of antibiotic resistance in organisms important in human pathology is the use of antibiotics in man. Although I still think the use of antibiotics on animals which share human homes needs to be looked at with care too.

Rolfe.
 
The words should have been "treated regularly ", man did I step in a pile of cow dung ( pun intended). Seems there's as many nut jobs out there in regard to " factory farming" and over utilization of antibiotics as in my radiation scenario.

My observation was from memory ( perhaps faulty) about a Nova show on PBS in regard to a spate of food borne pathogens that had recently caused deaths and illness in the US. E.Coli, Lysteria, C.Parvum...

The US has different standards then the EU or Japan in prophylactic use on antibiotics in feed and via injection. One on the consensus' of the "experts "was the over use and residual amounts of A-Bs in Human food. I had no idea this was a favorite PETA-Vegan topic - jeez! Like I proclaimed I am out on my area here.
 
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