Potent, if pungent, discovery
MONDAY OCTOBER 22 2001
SCIENCE BRIEFING BY ANJANA AHUJA [London Times]
When you go to hospital the last thing you want is to
contract the “superbug” MRSA
When you go to hospital the last thing you want is to contract the
“superbug” MRSA (methicillin-resistant staphylococcus aureus). A
nasty bacterium that can be harboured harmlessly by healthy
people, it can poison fatally the blood of those with vulnerable
immune systems.
Since it is resistant to methicillin, doctors treat it with a cream,
Mupirocin, but this is not always effective. Now scientists at the
University of East London think that garlic may help where
conventional antibiotics have failed. Led by Dr Ronald Cutler of
the School of Biosciences, the scientists took 30 strains of MRSA
that had been isolated from patients in the Royal London Hospital
and St Bartholomew’s in London. All showed resistance to
several antibiotics, and many were resistant to Mupirocin.
In Petri dishes the strains were treated with a solution containing
allicin, the chemical responsible for garlic’s pungency. The
solution, AB1000, killed all strains, even when very dilute (250
parts per million).
The next step was to try to turn AB1000 into something that could
actually be used. Standard MRSA treatments include swabbing
nostrils and skin, where MRSA usually resides, with Mupirocin
cream. When AB1000 was formulated into a cream it could
vanquish its opponents at a concentration of 500ppm, which is
mild enough for use on the skin. Cutler, who will present his results
at a meeting in Chicago next month, has carried out dermatological
tests on patients, and reports no adverse reactions. The
researchers have also found a way to mask the aroma of garlic in
the cream by developing a fragrance nicknamed Bella.
Serendipity played a role in this discovery. “A student of mine had
experimented with allicin, and when she showed me the results I
thought that she had made a mistake,” Cutler recalls. “I asked her
to go away and do it properly, and, of course, she hadn’t done it
wrong at all, which is why we’re so excited.”
In 1999 more than 3,000 hospital outbreaks of MRSA were
reported. That number rises steadily year on year, reflecting the
ability of the bacterium to evolve resistance. One of the reasons
that resistance has become such a problem is the overuse of
treatments such as Mupirocin. If the bacterium comes into contact
with the drug but is not killed by it, it is likely to evolve ways to
outwit its foe. Doctors also try to attack the bugs with several
antibiotics, in an effort to leave no biological niches in which the
bug can survive. A new antibiotic introduced only last year,
Linezolid, is already becoming ineffective against some strains.
Cutler and his colleagues now plan to test the ointment on hospital
patients with MRSA. AB1000 has the potential to become an
important new weapon in the fight against superbugs. |
