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Epidemiology
US Study Points to Strong New Class of Antibiotics
Three naturally occurring antibacterial compounds hold promise
for a new class of antibiotics, offering hope for fresh weapons against infection
at a time when older drugs are losing their punch, researchers report in the
journal Cell.
The new agents may even provide a quicker cure for tuberculosis
(TB), which could help people stick to the prescribed therapy better and reduce
the development of resistant strains. "The three antibiotics are attractive
candidates for development as broad spectrum antibacterial agents," said
Richard Ebright of Rutgers University in New Brunswick, New Jersey. Ebright
and colleagues showed how the three antibiotic compounds -- myxopyronin, corallopyronin
and ripostatin -- block the action of bacterial RNA polymerase, an enzyme needed
by bacteria to unlock genetic information from DNA needed to make proteins.
All three compounds are naturally produced by some bacteria for use in a kind
of chemical warfare against other bacteria. The agents work by taking advantage
of a design flaw in bacterial RNA polymerase. "RNA polymerase has a shape
reminiscent of a crab claw, with two prominent pincer-like projections,"
Ebright said in a statement. "Just as with a real crab claw, one pincer
stays fixed and one pincer moves -- opening and closing to keep DNA in place."
All three antibiotics work by jamming the pincer hinge, keeping the bacteria
from letting DNA into the enzyme.
Without the needed genetic code, the bacteria cannot make
proteins. This understanding has allowed the researchers to find ways to tinker
with the chemical structure of the antibiotic targets to make them even more
potent. The compounds appear to work against a broad range of bacteria, including
the bacteria that causes tuberculosis, which infects about a third of the world's
population. Current TB drugs known as rifamycins also act on RNA polymerase,
but they do it in a different way.
"As a result, these antibiotics can function simultaneously
with rifamycins and can be co-administered with rifamycins for more rapid clearance
of infection," Ebright said.
Reuters
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