‘Nightmare superbug’ found in the U.S
Is the discovery of a potentially serious bacteria resistant to antibiotics of last resort the nightmare scenario doctors have long been warning us about?
Military researchers in the United States have identified the first
patient, in the U.S., to be infected with bacteria that are resistant to
an antibiotic that was the last resort against drug-resistant germs.
The patient is well now, but the case raises the spectre of superbugs
that could cause untreatable infections, because the bacteria can easily
transmit their resistance to other germs that are already resistant to
additional antibiotics. The resistance can spread because it arises from
loose genetic material that bacteria typically share with one another.
“Think of a puzzle,” said Dr. Beth Bell, of the Centers for Disease
Control and Prevention (CDC). “You need lots of different pieces to get a
result that is resistant to everything. This is the last piece of that
puzzle, unfortunately, in the United States. We have that genetic
element that would allow for bacteria that are resistant to every
antibiotic.”
Colistin resistant
The bacteria are resistant to a drug called colistin, an old antibiotic that in the U.S. is held in reserve to treat especially dangerous infections that are resistant to a class of drugs called carbapenems. If carbapenem-resistant bacteria, called CRE, also pick up resistance to colistin, they will be unstoppable.
The bacteria are resistant to a drug called colistin, an old antibiotic that in the U.S. is held in reserve to treat especially dangerous infections that are resistant to a class of drugs called carbapenems. If carbapenem-resistant bacteria, called CRE, also pick up resistance to colistin, they will be unstoppable.
“This is huge,” said Dr. Lance Price, a researcher at George Washington
University. “We are one step away from CRE strains that cannot be
treated with antibiotics. We now have all the pieces in place for it to
be untreatable.”
The gene for resistance to colistin was first found in China, where the
drug is used in pig and poultry farming. Researchers reported its
discovery there in November. It has also been found in the intestine of
one pig in the U.S. CRE is still relatively rare, causing just 600
deaths a year, but by 2013, researchers had identified it in health care
facilities in 44 states. Dr. Thomas R. Frieden, director of the CDC,
often calls it the “nightmare superbug,” because it is resistant to all
but one antibiotic — colistin.
“We risk being in a post-antiobitic world,” he said during a gathering
for journalists in Washington on Thursday. “That wouldn’t just be
urinary tract infections or pneumonia — that could be for the 6,00,000
patients a year who need cancer treatment.”
He added: “The medicine cabinet is empty for some patients.”
The colistin resistance in the U.S. came to light when a 49-year-old
woman, who Dr. Bell said was “connected to the military”, was treated
for a urinary infection at a military clinic in Pennsylvania. Because
her urine culture had unusual results, the sample was sent to the Walter
Reed National Military Medical Center, which identified the drug
resistance. The bacteria, though resistant to colistin and some other
antibiotics, were not resistant to carbapenems. Doctors there published a
report on the case in a medical journal.
Patrick McGann, a scientist at the Walter Reed Army Institute of
Research and lead author of the paper, said researchers had only started
analysing samples a few weeks ago. They tested samples from six
patients, and one of them was the woman’s.
Dr. Bell said researchers did not know how the patient contracted the
resistant bacteria. The microbes have been found in people in Asia and
Europe, but the patient had not travelled during the past five months.
It is possible that she contracted the bacteria from food, or from
contact with someone else who was infected, she said.
Public health workers will interview the woman and will probably test
her family members and other close contacts for the bacteria, Dr. Bell
said.
Infectious disease doctors have long warned that overuse of antibiotics
in people and in animals put human health at risk by reducing the power
of the drugs, some of modern medicine’s most prized jewels. About two
million Americans fall ill from antibiotic-resistant bacteria every year
and at least 23,000 die from those infections. The Obama administration
has elevated the issue, laying out a strategy for how to bring the
problem under control. CRE germs usually strike people receiving medical
care in hospitals or nursing homes, including patients on breathing
machines or dependent on catheters. Healthy people are rarely, if ever,
affected. But the bugs attack broadly, and the infections they cause are
not limited to people with severely compromised immune systems. CRE was
believed to be the cause of infections from improperly cleaned medical
scopes that led to the death of two people at Ronald Reagan UCLA Medical
Center in California last year.
The Department of Defense, in a blog post about the discovery of the
gene in the United States, said it gives “a new clue into the antibiotic
resistance landscape.”
But the gene is rare: The blog pointed out that federal health
researchers had searched for the gene in 44,000 samples of Salmonella
and 9,000 samples of E. coli/Shigella, taken from people and retail
meat, and did not find it. — New York Times News Service
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