NDM-1 stands for New Delhi metallo-ß-lactamase-1. It was first isolated in a Swedish patient of Indian origin who travelled to India in 2008. What led to the emergence of NDM-1 in India is not clear.
It has been found to be widespread in India, and by 2015, it had been detected in more than 70 countries worldwide.
What is NDM-1?
NDM-1 itself does not cause disease, but it has the potential to change the characteristics of bacteria. It makes them resistant to antibiotics. In this way, it can lead to a range of conditions, from a urinary tract or bloodstream infection to a wound infection, or pneumonia.
Bacteria that express NDM-1 cannot be defeated using antibiotics.
Carbapenems are the most powerful antibiotics. They are used as a last resort for many bacterial infections, such as E. coli and Klebsiella pneumoniae carbapenemase (KPC).
The NDM-1 gene causes 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 KPC as emerging issues in the field of infectious diseases.
A bacterium carrying the NDM-1 gene is the most powerful superbug in existence.
NDM-1 is different from MRSA, another superbug, because MRSA is Gram-positive, while the infections that carry NDM-1 are Gram negative. They are different strains.
Why is NDM-1 dangerous?
The World Health Organization (WHO) is concerned that NDM-1 could be ushering in "the doomsday scenario of a world without antibiotics."
Before the discovery of antibiotics in 1928, many people died 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. As they spread around the world, it could lead to a health crisis.
The WHO say that a pregnant woman, for example, could develop a kidney infection that spills over into the bloodstream with a strain containing NDM-1. In this case, there would be no treatment options.
The NDM-1 gene causes bacteria to produce an enzyme called a carbapenemase. Carbapenemase makes nearly every antibiotic ineffective, including carbepenem.
Carbepenem antibiotics are extremely powerful drugs that are used to fight highly resistant bacteria when other antibiotics have not worked. Even carbepenem is ineffective in cases of NDM-1.
A bacterium with the NDM-1 DNA code has the potential to be resistant to all our current antibiotics, as well as new antibiotics that could become available in the near future. Research is currently under way to find a solution to NDM-1.
How does NDM-1 spread?
The DNA code for NDM-1 can jump from one bacteria strain to another through a process known as horizontal gene transfer (HGT).
If NDM-1 jumps to a bacterium that is already antibiotic-resistant, some dangerous infections could emerge, which would spread rapidly between people. These infections might be untreatable.
In 2010, scientists were aware that some strains of bacteria, such as E. coli and Klebsiella pneumoniae (KPC), carry the NDM-1 gene. It has since been found that horizontal gene transfer (HGT) is possible between KPC and NDM-1.
Has NDM-1 already spread?
The NDM-1 gene was named after New Delhi, the Indian capital. The gene is widespread in India and Pakistan, especially in hospitals.
It initially occurred mainly in in India and Pakistan, and specifically in New Delhi, where the climate encourages its persistence year round. It has been found in drinking water and the holy rivers of India, such as the Ganges.
NDM-1 has surfaced in countries countries around the world, including the United States, Japan, Australia, and the United Kingdom, in patients who spent time or travelled in India or have family members there.
Some patients carried the disease home after traveling to India or Pakistan for cosmetic surgery, because this type of treatment is cheaper in Asia.
However, the ability of NDM-1 to spread to other kinds of bacteria means that scientists are expecting to see numerous secondary cases in other countries that are not related to time spent in India.
Can NDM-1 be defeated?
At the moment, the only way to combat the spread of NDM-1 is through surveillance, quickly identifying and isolating infected patients, disinfecting hospital equipment, and 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 there is no effective treatment 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.
Good hand hygiene is key to preventing the spread of infection.
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, for research budgets to be increased, pharmaceutical companies to "show more responsibility and commitment," and for scientists to find new ways of approaching the "crisis of resistant Gram-negative infections."
Since 2001, the WHO have urged health professionals to reduce the use of antibiotics to reduce the risk of diseases developing resistance, and to keep the use of carbapenem antibiotics 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 if medical use of antibiotics is controlled, concern remains about the agricultural use of antibiotics, as these are can enter the human system by passing into food and leaching into the environment.