- Dr. Joshua Lederberg discovered bacteria gene swapping.
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- Antibiotic-resistant bacteria kill more than 40,000 North
Americans a year, and the numbers will soar unless the so-called super-germs
are brought under control, a new book warns.
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- The book, The Killers Within, charts the acceleration
of resistant infections that began with a few cases in the late 1980s and
is now spiralling out of control. The germs, once killed easily with standard
antibiotics, can disintegrate skin, clog the lungs and carve golf-ball-size
abscesses in flesh.
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- "The bad bugs are getting stronger and they're getting
stronger faster," says co-author Mark Plotkin, a Smithsonian Institution
ethnobotanist whom Time magazine dubbed a "Hero of the Planet"
in 1998. "We feel like we're looking at almost a hyper-evolutionary
period," he says.
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- While West Nile virus is grabbing headlines for killing
about 100 people, the U.S. Centers for Disease Control and Prevention estimates
44,000 people in North America die annually of infections from drug-resistant
germs.
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- Some experts believe the numbers are higher. The epidemic
comes as pharmaceutical companies have all but stopped doing research on
antibiotics.
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- "They'd rather develop lifestyle drugs like Viagra
and blood-pressure medicine that you're going to take every day of your
life for 40 years," says Dr. Plotkin, who concedes a few drug companies
are pursuing new antimicrobials.
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- "If you're selling antibiotics, I'm going to take
it for a week, and I'm either going to get better or I'm going to die."
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- Even the newest types of antibiotics, such as Synercid
and Zyvox, are already threatened by resistant strains.
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- The book charts the proliferation of three germs in particular:
E. faecium, S. aureus and S. pneumococcus, which are remarkably common
in hospitals. Virtually every major Canadian hospital has been colonized
by these bacteria, including operating theatres and intensive care wards.
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- Decades ago, these species could be wiped out with a
single dose of penicillin.
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- But overuse of antibiotics gave the bacteria a chance
to develop new genes that protected them.
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- "Among the billions of bacteria in a drop of human
blood, or on a pinpoint of skin ... might be a few -- just a few -- with
a chance mutation that enabled them to resist the antibiotic used against
them," the book notes.
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- "If the antibiotic was then removed because the
patient felt better and stopped using it, those few resistant bugs would
have an ecological niche, or clear field, in which to run wild."
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- Unlike other creatures, bacteria can swap genes between
species, so enterococci can donate genes to staphylococcus.
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- Joshua Lederberg, the Nobel laureate who discovered this
gene swapping, says the Ebola and West Nile viruses are minor by comparison
with such bacteria.
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- "The odds of Ebola breaking out are quite low, but
the stakes are quite high," says Dr. Lederberg, a professor at Rockefeller
University in New York.
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- "With antibiotic resistance, the odds are certain
and the stakes are just as high."
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- Unlike U.S. hospitals, which have thrown up their hands
in the face of drug-resistant enterococci and other bugs, Canadian hospitals
have fought back.
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- Two of the heroes of The Killers Within are microbiologist
Donald Low and infectious disease specialist Alison McGeer, both from Toronto,
who have waged an exhaustive struggle against drug-resistant germs.
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- As early as 1991, Dr. Low was warning about the dangers
of overuse of antibiotics.
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- By 1993, a Japanese patient had become infected with
the first strain of S. aureus that could not be killed by Vancomycin, known
as the "antibiotic of last resort."
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- One of the biggest areas of antibiotic misuse is by doctors
who prescribe them to complaining patients with viral infections.
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- Antibiotics do not work against viruses and the more
often an antibiotic is given, the more likely a person's natural bacteria
will become resistant.
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- Adding to the medical overuse of antibiotics, North American
livestock have been fed small doses of antibiotics as a growth promoter
since the 1950s.
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- As a result, livestock serve as a reservoir of drug-resistant
germs.
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- One of the reasons the new antibiotic, Synercid, is now
threatened with resistance is because cows are being fed an analogue --
a close chemical cousin -- of the drug with their dinner.
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- The book says experimental drugs offer some hope.
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- Among the most unorthodox of these is a tiny chunk of
protein, found in the thick saliva of the Komodo dragon, a massive carnivore
found in Indonesia.
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- Another promising drug can be found in the skin of African
clawed frogs.
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- In the meantime, infection control and less antibiotic
use in humans and animals is the only strategy, Dr. Plotkin says.
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- bevenson@nationalpost.com
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- http://www.nationalpost.com/home/story.html?id={D75C24A3-81F2-4665-BF11-5B8641F7C2F9}
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