Laboratory researchers say they've discovered a new
antibiotic that could prove valuable in fighting
disease-causing bacteria that no longer respond to
older, more frequently used drugs. The new
antibiotic, teixobactin, has proven effective
against a number of bacterial infections that have
developed resistance to existing antibiotic drugs.
Researchers have used teixobactin to cure lab mice
of MRSA (methicillin-resistant Staphylococcus aureus),
a bacterial infection that sickens 80,000 Americans
and kills 11,000 every year, according to the U.S.
Centers for Disease Control and Prevention (CDC).
The new antibiotic also worked against the bacteria
that causes pneumococcal pneumonia. Cell culture
tests also showed that the new drug effectively
killed off drug-resistant strains of tuberculosis,
anthrax and Clostridium difficile, a bacteria that
causes life-threatening diarrhea and is associated
with 250,000 infections and 14,000 deaths in the
United States each year, according to the CDC. "My
estimate is that we will probably be in clinical
trials three years from now," study’s senior author
said. He said researchers are working to refine the
new antibiotic and make it more effective for use in
humans. Most antibiotics are created from bacteria
found in the soil, but only about 1 percent of these
microorganisms will grow in petri dishes in
laboratories, he added. Because of this, it's become
increasingly difficult to find new antibiotics in
nature. The 1960s heralded the end of the initial
era of antibiotic discovery, and synthetic
antibiotics were unable to replace natural products,
the authors said in background notes. In the
meantime, many dangerous forms of bacteria have
developed resistance to antibiotics, rendering
useless many first-line and even second-line
antibiotic treatments. Doctors must use less
effective antibiotics that are more toxic and more
expensive, increasing an infected person's chances
of death. The CDC estimates that more than 2 million
people are sickened every year by
antibiotic-resistant infections. "Pathogens are
acquiring resistance faster than we can come up with
new antibiotics, and this of course is causing a
human health crisis," he said. Senior author and his
colleagues said they have figured out how to use
soil samples to generate bacteria that normally
would not grow under laboratory conditions, and then
transfer colonies of these bacteria into the lab for
testing as potential sources of new antibiotics.
"Essentially, we're tricking the bacteria," he said.
"They don't know that something's happened to them,
so they start growing and forming colonies." A
start-up company, NovoBiotic Pharmaceuticals of
Cambridge, Mass., used this technology to discover a
group of 25 potential new antibiotics, Lewis said.
Teixobactin "is the latest and most promising" of
those new leads, he said. Teixobactin's potential
effectiveness suggests that the new technology "is a
promising source in general for antibiotics, and has
a good chance of helping revive the field of
antibiotic discovery," he explained. Teixobactin
kills bacteria by causing their cell walls to break
down, similar to an existing antibiotic called
vancomycin, the researchers said. It also appears to
attack many other growth processes at the same time,
giving the researchers hope that bacteria will be
unable to quickly develop resistance to the
antibiotic. "It would take so much energy for the
cell to modify that I think it's unlikely resistance
will appear," study co-author said. The authors note
that it took 30 years for resistance to vancomycin
to appear, and they said it will probably take even
longer for genetic resistance to teixobactin to
emerge. |