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DM-1
refers to a gene's protein product that some bacteria make. A bacterial strain
that carries NDM-1 will be resistant to even some of the strongest antibiotics.
Few
current antibiotics can combat bacteria that have
the NDM-1 gene, making it potentially dangerous.
NDM-1 stands for New Delhi metallo-ß-lactamase-1. A medical team first isolated the gene in a Swedish
patient of Indian origin who traveled to India in 2008.
What led to the emergence of NDM-1 in India is not clear.
This superbug is widespread in India, and, by 2015, researchers and
medical experts detected it in more than 70 countries worldwide.
In this article, we explore the nature and possible dangers of bacteria
with the NDM-1 gene.
What is NDM-1?
An NDM-1 superbug is resistant to almost all antibiotics.
The NDM-1 protein product itself does not cause disease, but it has the
potential to change the characteristics of bacteria.
The gene makes bacteria resistant to antibiotics. In this way, it can lead
to a range of conditions, such as a urinary tract, bloodstream, or wound infections
and pneumonia.
Carbapenems are among the most powerful antibiotics. Healthcare
professionals use them as a last resort for many bacterial infections, such as
those that E. coli and Klebsiella pneumoniae cause.
The NDM-1 gene allows the bacterium to produce an enzyme that neutralizes
the activity of these antibiotics.
The Centers for Disease Control and Prevention (CDC) have classified NDM-1
and another similar protein called KPC as emerging issues in
the field of infectious diseases.
A bacterium carrying the NDM-1 gene is considered a very powerful
superbug.
The NDM-1 protein is different from the protein product that characterizes
methicillin-resistant Staphylococcus aureus (MRSA), another superbug. MRSA are a
Gram-positive bacteria, while the bacteria that carry NDM-1 are Gram-negative,
a different classification of bacteria.
Possible dangers
The World Health Organization (WHO) is concerned that NDM-1 could see in
"the doomsday scenario of a world without antibiotics."
Before the discovery of antibiotics in 1928, many people died because of
infections that are now avoidable.
NDM-1 raises fears that diseases in the future will not respond to
antibiotics. If NDM-1 crosses over into other bacteria, secondary diseases will
emerge, causing a health crisis as
they spread around the world.
The WHO suggest that a woman who is pregnant, for example, could develop a kidney infection that transfers into the
bloodstream with a strain containing NDM-1. In this case, no treatment options
would be available that are safe for a woman during pregnancy.
The NDM-1 gene causes bacteria to produce an enzyme called a
carbapenemase. Carbapenemase renders many preferred types of antibiotic
ineffective, including carbapenems.
Carbapenem antibiotics are extremely powerful drugs that can counter the
activity of highly resistant bacteria for which other antibiotics have not been
effective. Even
carbepenems are ineffective in cases of NDM-1.
carbepenems are ineffective in cases of NDM-1.
A bacterium with a plasmid containing the NDM-1 protein product has the
potential to be resistant to many current antibiotics, as well as newer
antibiotics that could become available in the near future.
Research is on-going into possible solutions to NDM-1.
Transmission
The plasmid containing the genetic code for NDM-1 can move from one strain
of bacteria to another through a process known as horizontal gene transfer
(HGT).
If NDM-1 jumps to a bacterium that is already antibiotic-resistant,
dangerous infections could emerge. These would spread rapidly between people
and might not be treatable.
In 2010, researchers became aware that some strains of bacteria, such as E. coli and Klebsiella pneumoniae,
carry the gene that produces NDM-1. They have since learned that horizontal
gene transfer (HGT) between bacteria that express KPC and NDM-1 is possible.
Has NDM-1 already spread?
Scientists expect that secondary NDM-1 viruses will spread without a person having come into contact with India.
The people who discovered the NDM-1 protein named it after New Delhi, the
Indian capital. The gene for this is widespread in bacteria found in India and
Pakistan, especially in hospitals.
It initially occurred mainly in India and Pakistan, and specifically in
New Delhi, where the climate encourages its persistence year round. Since then,
it has occurred in drinking water and
the holy rivers of India, such as the Ganges.
Bacteria expressing NDM-1 have surfaced in
countries around the world, including the United States, Japan, Australia, and
the United Kingdom, in patients who spent time in India, traveled through it,
or have family members there.
Some people carried the infection home after traveling to India or
Pakistan for cosmetic surgery, as this type of treatment is less expensive in
Asia.
However, the ability of the NDM-1 gene to spread to other kinds of
bacteria means that scientists are expecting to see numerous
secondary cases in other countries that do not have links to time spent in
India.
Solutions
At the moment, the only way to combat the spread of bacteria expressing
NDM-1 is through the following measures:
·
surveillance
·
quickly
identifying and isolating patients with the bacteria
·
disinfecting
hospital equipment
·
following
hand-hygiene procedures in hospitals
So far, patients with NDM-1-related infections have been treated on a
case-by-case basis, with a combination of medications, but few effective and no
oral treatments are available for many of the infections caused by NDM-1.
Some strains of bacteria are totally resistant to virtually all kinds of
antibiotic.
In 2014,
Morad Hasssani of the Albert Einstein College of Medicine in New York, NY,
called on "all stakeholders in this public health crisis" to do their
part, including an increase in research budgets, increased responsibility and
commitment from pharmaceutical companies, and new approaches from medical
scientists.
Since 2001, the WHO has urged health professionals to reduce the use of antibiotics and
bring down the risk of resistance in bacterial diseases. This also involves
keeping carbapenem use to a minimum.
The Center for Disease Dynamics, Economics and Policy note that
"antibiotic resistance is a direct result of antibiotic use." Europe,
Canada, and the United States have reduced their use of antibiotics in recent
years, but usage is still increasing in
India, Sub-Saharan Africa, Latin America, and Australia.
Even as medical use of antibiotics reduces, concerns remain about the
agricultural use of antibiotics, as these might enter the human system in food
and leak into the environment.
Takeaway
The NDM-1-expressing superbug is a potentially dangerous bacterium that
could become resistant to many types of antibiotic, spreading quickly.
NDM-1 refers to a gene product present in some bacteria that counters
antibiotics. If bacteria expressing this gene start to spread, treatment using
currently available measure will not be possible.
The first signs of the bug occurred in India and have spread through
travel. Overuse of antibiotics increasing the risk of NDM-1 expression and
transferring to other bacteria through a process called HGT.
Surveillance, the isolation of patients with the infection, and good
hospital hygiene are the only protective measures available at present.
Q:
Am I at risk of catching a superbug?
A:
Risks associated with coming into contact with a
superbug typically include admission to a hospital with poor antibiotic
stewardship practices, travel to a high-risk location, and having received many
different antibiotics.
While not always avoidable, these risk factors can
increase the likelihood of coming in contact with a superbug.
You can reduce your risk by taking antibiotics
precisely as recommended by a doctor and obtaining preventative care in an
outpatient setting when possible.
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