Plaque bomb

Dentists could soon be out of a job - a "smart bomb" antimicrobial drug
that kills the bacteria that live in plaque could stop tooth decay in
its tracks.

Traditional antibiotics are too indiscriminate to be used against
/Streptococcus mutans/ because they also kill commensal or "friendly"
bacteria, paving the way for other mouth infections. Now Wenyuan Shi of
the University of California, Los Angeles, has created an antimicrobial
that spares commensal bugs.

He linked a peptide that specifically targets /S. mutans/ to the active
region of Novispirin G10, a broad-spectrum antibiotic that destroys
bacterial membranes. The compound killed /S. mutans/ grown in liquid or
as biofilms without harming other oral streptococci (/Antimicrobial
Agents and Chemotherapy/, vol 50, p 3651).

Giving the antimicrobial as a one-off treatment, or at regular
intervals, to kill off /S. mutans/ might enable less harmful bacteria to
colonise its niche, says Shi, making it more difficult for the bug to
regain a toehold. It is unlikely that the bug would develop resistance
to the drug because it would have to go through multiple mutations to
thwart membrane destruction, he adds.

Shi believes that such "selectively targeted antimicrobial peptides" or
STAMPS, might also work against other infections in mixed microbial
environments such as the middle ear, vagina and gastrointestinal tract.

From issue 2578 of New Scientist magazine, 22 November 2006, page 21
Original Article