Rare genetic fusion caused superbug NDM1, study finds
By Kounteya Sinha & Durgesh Nandan Jha, from The Times of India
NEW DELHI: A “highly rare genetic fusion” between two previously-known antibiotic-resistant genes gave birth to the dangerous Indian superbug metallo-beta-lactamase, NDM1.
This fusion also gave NDM1 the power to easily jump between various species of bacteria at superfast speed and consequently making them drug resistant.
British scientists, who first reported the NDM1 last year, has now found through genetic DNA studies that NDM1 – by jumping between bacteria strains – can make several diseases they cause in humans, resistant to known antibiotics.
The latest study published in the medical journal, “Antimicrobial Agents and Chemotherapy”, also dismisses the argument that the superbug NDM1 has been in the environment for many years.
The study’s lead author Dr Mark Toleman from the University of Cardiff said “We now know that NDM1 got created very recently and any ideas that suggest it is found everywhere and has been around for ever are baseless.”
He added, “Usually the DNA of such genes change frequently. However, in NDM1 we saw no such change, hence it has recently been created. It may have originated from a bacterium in the environment that didn’t harm humans. After the fusion, it started jumping from one bacterium to another making several diseases caused by them resistant to drugs.
It spreads mostly through fecal oral route. It’s a rare fusion event that gave birth to NDM1.”
The team says that when they first reported the existence of the NDM1, it was isolated only in E Coli
Now, it has jumped to over 20 different species of bacteria. The latest study says, “This is unequivocal evidence that NDM1 is a chimera.” A chimera is a single organism that is composed of two or more different populations of genetically distinct cells originating from different entities.
The study says, “We sequence comparisons to show that NDM1 is a chimeric gene that has risen by the fusion of a pre-existing MBL gene with the resistance gene aphA6. We propose that the resulting changes in NDM1 expression and the properties of the expressed protein partially explain the greater success with which NDM1 has disseminated as compared to other MBLs that confer a similar resistance type.”
Dr Chand Wattal, chairman of department of clinical microbiology at Sir Ganga Ram Hospital, said, “The genetic fusion between antibiotic resistant genes is possible and NDM1 could be a result of it.”
Dr M C Misra, chief of the AIIMS Trauma Centre, said that mutation of genes is a natural process and it has been seen that the new species that evolve through the process are more virulent.
“This phenomenon is present across the world. But in India, the risk is bigger because misuse and abuse of antibiotics are higher. There is possibility of even the commonest of bacteria and viruses treatable with first or second generation drugs at present getting resistant and untreatable,” said Dr Misra.
He said that a stringent policy of sale and purchase of antibiotics and its usage in hospital setting is the need of the hour.
The study adds, “Carbapenems are potent antibiotics that are reserved for life threatening bacterial infections. However, their effectiveness is increasingly compromised by resistance.
The NDM1 was unknown before 2008 and we have previously shown that it is widely disseminated in the UK and South Asia. We have also identified NDM1 genes in a broad range of bacteria isolated from the environment in New Delhi including the serious pathogens Shigella boydii and Vibrio cholerae. Possession of NDM1 confers resistance to all classes of antibiotics like penicillin, cephalosporin and carbapenem
Dr. Pinna says:
This is the beginning of the end of the Era of Antibiotics.
As we know from Darwin’s Theory of the Survival of the Fittest, all species undergo genetic changes with each generation.
Since humans take approximately twenty years for each generation and there were relatively few humans, our genes have not changed much in the last 100,000 years.
But, bacteria are quite different. They multiply within hours and there are hundreds of trillions of them. The genes of bacteria are constantly challenging their environment.
Prior to the discovery of Penicillin (a fungus) by Dr. Fleming in 1928, humans had no external way of combating infectious disease.
Humans who developed bacterial infections either killed the bacteria with their immune system or they succumbed to the infection, and the bacteria became the victors.
With the advent of penicillin, followed by “sulfa drugs” and then a wide spectrum of differing antibiotics, the battle ground changed.
Humans could deal with most bacterial infections through the use of antibiotics. Of course, the Immune System played more than an ancillary role as we saw when patients became infected with the AIDS virus.
However, the combination of a strong immune system and wisely used antibiotics turned out to be a victorious combination for medical doctors treating patients with bacterial infections.
Doctors were trained to find out which bacteria was causing the illness and then use the appropriate antibiotic.
This type of treatment became a specialty in itself, and today we have Infectious Disease specialists who determine what bacteria are causing the illness and which specific antibiotics will kill those bacteria.
All medical students are taught in medical school: “Do not use antibiotics indiscriminately!
The Law of Survival of the Fittest will produce “Super-Bacteria” if antibiotics are used blindly.
In most countries, physicians use antibiotics carefully. However, in many poor countries, antibiotics are given at the whim of the patient—simply to earn a fee.
In India, the worst of all possible scenarios has arisen–THE PUBLIC DECIDES WHEN TO USE ANTIBIOTICS! In India, any person with an infection can go to a pharmacy and buy any antibiotic! This has led to widespread antibiotic use.
It must be remembered , India has a population of one and a half billion people. The inevitable has occurred.
As Charles Darwin predicted, in the face of adversity, species will change genetically. Those that can overcome the environment, in this case, the antibiotics, will survive and grow.
Today, we are seeing bacteria which are resistant to all antibiotics.
If the patient’s immune system cannot kill the bacteria, the patient dies. And, patients infected with the super bug are dying, in hospitals across the world!
WHAT DOES THIS MEAN?
The new “Super Bugs” are giving their resistance to other bacteria. Humans infected with the new bacteria cannot be treated with antibiotics. These humans, mostly on the Indian Sub-continent, are traveling to the rest of the world, carrying the super bugs with them.
Doctors are now finding that their local patients are being infected with the super bugs, and they have no way of treating them.
This is now happening in Europe, the USA, and many Pacific countries, where Indians and Bangladeshis frequently go. Within a few years the entire world will be covered with the super bugs and all our present antibiotics will be useless.
Because of the complex enzyme make-up of the bacterial cell wall, there is no known method anywhere for killing this new species of bacteria.
Within several years, survival from an infection will depend solely on the strength of a human’s immune system.
Big Pharma has tried to make new antibiotics and has failed! There are no new useful antibiotics in the pipeline which will kill the super bugs. Medical Scientists are looking at how doctors dealt with infection in the 19th century.
The ERA OF ANTIBIOTICS has quietly ended.