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Crocodile blood may yield antibiotics
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.
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 US 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 said. 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," Dr Britton said from Darwin's Crocodylus Park, a tourism
park and research center.
Dr Britton said the crocodile immune system worked differently from the
human system by directly attacking bacteria as soon as 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 Dr Britton and Dr 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 Dr 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 Dr Merchant.
However, the crocodile's immune system may be too powerful for humans and
may need to be synthesized 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 Dr Britton. (theaustralian.news.au/IM)
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