NEWS:Crocodile blood may yield powerful new antibiotics

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Aug. 16, 2005, 8:18AM

Crocodile blood may yield powerful new antibiotics

Reuters News Service

SYDNEY - Scientists in Australia's tropical north are collecting blood

from crocodiles in the hope of developing a powerful antibiotic for

humans, after tests showed that the reptile's immune system kills the

HIV virus.

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The crocodile's immune system is much more powerful than that of

humans, preventing life-threatening infections after savage territorial

fights which often leave the animals with gaping wounds and missing

limbs.

" They tear limbs off each other.and despite the fact that they live in

this environment with all these microbes, they heal up very rapidly and

normally almost always without infection, " said U.S. scientist Mark

Merchant, who has been taking crocodile blood samples in the Northern

Territory.

Initial studies of the crocodile immune system in 1998 found that

several proteins (antibodies) in the reptile's blood killed bacteria

that were resistant to penicillin, such as Staphylococcus aureus or

golden staph, Australian scientist Adam Britton told Reuters on

Tuesday. It was also a more powerful killer of the HIV virus than the

human immune system.

" If you take a test tube of HIV and add crocodile serum it will have a

greater effect than human serum. It can kill a much greater number of

HIV viral organisms, " Britton said from Darwin's Crocodylus Park, a

tourism park and research centre.

Britton said the crocodile immune system worked differently from the

human system by directly attacking bacteria immediately an infection

occurred in the body.

" The crocodile has an immune system which attaches to bacteria and

tears it apart and it explodes. It's like putting a gun to the head of

the bacteria and pulling the trigger, " he said.

For the past 10 days Britton and Merchant have been carefully

collecting blood from wild and captive crocodiles, both saltwater and

freshwater species. After capturing a crocodile and strapping its

powerful jaws closed the scientists extract blood from a large vein

behind the head.

" It's called a sinus, right behind the head, and it's very easy just to

put a needle in the back of the neck and hit this sinus and then you

can take a large volume of blood very simply, " said Britton.

The scientists hope to collect enough crocodile blood to isolate the

powerful antibodies and eventually develop an antibiotic for use by

humans.

" We may be able to have antibiotics that you take orally, potentially

also antibiotics that you could run topically on wounds, say diabetic

ulcer wounds; burn patients often have their skin infected and things

like that, " said Merchant.

However, the crocodile's immune system may be too powerful for humans

and may need to be synthesised for human consumption.

" There is a lot of work to be done. It may take years before we can get

to the stage where we have something to market, " said Britton.

http://www.chron.com/cs/CDA/ssistory.mpl/health/3312354

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