Medical News
New antibiotics offer hope
in face of antimicrobial resistance
Scientists discover drugs that act differently from existing antibiotics
A
new group of antibiotics with a unique approach
to attacking bacteria has been discovered,
giving scientists fighting against antimicrobial
resistance a rare boost.
The discovery comes from a family of antibiotics
called glycopeptides that are produced by soil
bacteria.
Two of these, corbomycin and complestatin, have
been found to kill bacteria in a way that hasn’t been
seen before, by blocking the way their cell walls work.
It’s also been demonstrated in mice that they
can prevent infections caused by the drug-resistant
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MAY 2020
Staphylococcus aureus, a group of bacteria that can
cause many serious infections.
“Bacteria have a wall around the outside of their
cells that gives them shape and provides a source of
strength,” said Beth Culp, a biochemistry specialist at
McMaster University who has been researching the
way these walls work.
“Antibiotics like penicillin kill bacteria by preventing
the wall being built, but the antibiotics that we found
actually work by doing the opposite — they prevent
the wall from being broken down. This is critical for
cells to divide.
“In order for a cell to grow, it has to divide and
expand. If you completely block the breakdown of the
wall, it’s like it’s trapped in a prison, and can’t expand
or grow,” she explained at the publication of her
research in Nature in February.
Looking at glycopeptides that lacked known
resistance mechanisms, Culp’s team considered how
they attack bacteria. They figured that if the genes that
made these antibiotics were different, the way they
killed the bacteria would also be different. They then
confirmed the bacterial wall action.
“This approach can be applied to other antibiotics
and help us discover new ones with different
mechanisms of action. We found one completely new
antibiotic in this study, but since then, we’ve found a
few others in the same family that have this same new
mechanism,” she said.
The new antibiotics work against several
problematic bacteria, including MRSA and the
bacterium that causes gonorrhoea, which is frequently
resistant to antibiotics.
Dr Andrew Edwards, of the Department of
Infectious Disease at Imperial College London, called
this an “exciting development” but said it shouldn’t yet
signal a breakthrough.
“While this is undoubtedly a major finding, there’s
still a long way to go before we can generate an
antibiotic that can be used in a clinical setting. Many
new antibiotics fail clinical trials because they’re found
to be too toxic or not sufficiently effective when given
to humans,” he told Global Health Asia-Pacific.
“Of the many thousands of promising new
pharmaceutical compounds that are discovered or
developed each year, only very few of them actually
get licensed after many years of further development
and testing,” he added. n
GlobalHealthAndTravel.com