Drug-Resistance Gene Hopping Between Superbug Strains in New Delhi Water

By Veronique Greenwood | April 8, 2011 9:45 am

What’s the News: A gene that makes bacteria resistant to up to 14 antibiotics has been discovered in bacteria in drinking water and street puddles in the Indian capital of New Delhi by a research team from the University of Cardiff in Wales. Scientists were already aware that microbes bearing this gene, which produces an enzyme called NDM-1, were infecting people in India, but it had been thought that such bacteria were mainly picked up in hospitals. This study shows that the gene, which is capable of jumping from species to species, is loose in the environment.

What’s the Context:

  • NDM-1 is in a class of enzymes that are known culprits in the spread of drug-resistance: the beta-lactamases. The first beta-lactamase, penicillinase, was discovered in 1940 ($, pdf). These enzymes give resistance to antibiotics like cephamycins, carbapenems, and penicillin, which have similar chemical structures.
  • The study is fueling fears that the NDM-1 gene could easily jump into bacteria around the world. Recently, a separate team of scientists showed that Swedish tourists returning from India had bacteria with beta-lactamases in their guts that they hadn’t had before the trip. And as the current study found that the gene for NDM-1 skipped easily among bacterial species, the researchers are calling for greater action to fight drug-resistant bacteria in developing countries.
  • Indian officials have spoken out against the study, in part over fears that it will damage India’s tourism industry. In an AP article, V.M. Katoch, director-general of the Indian Council of Medical Research, said, “We know that such bacteria with genes are in the atmosphere everywhere. This is a waste of time. The study is creating a scare that India is a dangerous country to visit. We are condemning it.”
  • This isn’t the first time we’ve heard of NDM-1: the gene has been on scientists’ radar since 2008, when it was first identified in a Swedish tourist returning from India. (For more background on the gene, see Scientific American’s coverage.)

Not So Fast:

  • The term “superbug” has been racing from media outlet to media outlet. But this is a bit of a misnomer: this isn’t a single new bacteria species endowed with phenomenal resistance, it’s a gene that can bestow it.
  • The difference is important. Dealing with a gene that can make any number of disease-causing bacteria resistant may be more difficult than focusing on just one species of bug—especially as the team found the gene in 20 types of bacteria, including those that cause dysentery and cholera. But the study’s findings suggest that the gene is much more likely to jump to new bacteria while outside the host (at temperatures typical of India’s climate, transfers were high; at body temperature, they dropped off). It would be interesting to see whether the fact that the gene needs lower temperatures to transfer could used to prevent its spread: if the transfer happens in drinking water, then better water treatment might help delay the formation of new resistant strains.

Reference: Toleman, M. et al. Dissemination of NDM-1 positive bacteria in the New Delhi environment and its implications for human health: an environmental point prevalence study. The Lancet Infectious Diseases, Early Online Publication, 7 April 2011. doi:10.1016/S1473-3099(11)70059-7

  • http://DiscoverMagazine Templar 7

    Here is a perfect example of why we shouln’t genetically modify cows’ milk to cirtain human genes,(To make the milk healthier for us), even though the intentions behind the idea seem right. What we will do is allow these genes to start species-hopping, creating a new wake of havoc upon humanity!!

    The problem is….if they effect the whole worlds’ milk supply at once…there will probably be no control to compare it against…bah…not my problem, right? WRONG<.

  • http://www.medifix.org/safec Dr Sri

    This is not the time to organise research to find out what is going on and how the bugs are hopping from one strain to another. We must act and be bold to say, yes lets find out how we can prevent the spread. In 1980s the bugs entered body through cuts, now through guts and is in the water and sewer not only in India but also in UK. We must stop this mud slinging and start listening to what we are saying. This is hard for people like me to be open because I do not enjoy spreading this message branded as “Negative” or “Pessimistic” nor do I want to believe what my subconscious mind has visualised. The only solution is to avoid coming in contact with the superbugs. If you don’t fancy getting mugged, please don’t go to Bronx (USA) or Brixton (UK) similarly avoid visiting health centres and hospitals.

  • Tom Hanna

    This is a classical scenario being repeated time and time again. Rabbits were hap hazardly introduced into the Australian ecology and multiplied like,… well rabbits. It was pandemic until the population reached a point that mother nature took over and introduced a simple little ear mite and brought the numbers down to a more managable level. India is boasting thier population at being what, a quarter or a fifth of the world’s. This planet is way over populated by humans and mother natare will step in again and take care of business, just as she has done in the past.
    Fight the super bugs all you want and yes, as a stereotypical mindless educated North American, do the fighting over seas, not on our soil, let that dam thing run ramped for a few years but then stop it before it takes hold over here. Just like Japan or Germany!
    We have science and we have history and mother nature gave us both to harness at our own free will. We do have to educate our third world countries to keep what is going to kill us from rearing it’s ugly head. The bird flu in China is a prime example of that.
    History will always repeat it self.

  • http://www.youtube.com/watch?v=OcJEUDhAuO0 Greg Brown

    We could be creating antibiotic resistant super bugs all over the developed world in our own bodies, our waterways and in the bodies of our livestock. Antibacterial chemicals such as Triclosan are not broken down and after being dumped down the drain have become prevalent in our waterways and drinking water etc. Bacteria of all types, when exposed to these chemicals, develop cross resistance to antibiotics. We also ingest and absorb these chemicals so super bugs can incubate inside our bowels. This likely occurs inside the bowels of wild and domestic animals as well. This could be a disaster in the making, right under our noses.

    Check out this video from Alberta, Canada:

  • dave chamberlin

    Reading the Science America link provides reasonable explanations rather than shrill ones. The cycle requires poor sanitation, and high temperatures. In India half of the population of 1.3, fully 650 million do not have flush toilets. Studies have also found that these genes are one million times more likely to species hop at high temperatures, which are only found in equatorial regions.

    Mark Twain said “history does not repeat itself, but it rhymes.” Up to about 1900 it was a terrible idea health wise for a northern European to visit the tropics. The death rate of British colonialists in India was up to 50% a year. I am quite sure these numbers will never return but I wonder if fear of super bugs will have an immense impact on tourism to these places.

    I just hope that birth control limits our population more than malthusian misery does. I don’t like it when people say anyone deserves a horrible fate because we should have known better. Yes we should have known better but to reduce us to a herd waiting to be culled is unnecessarily cold.

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    It is perfect time to make some plans for the future and it is time to be happy. I have read this post and if I could I desire to suggest you few interesting things or tips. Perhaps you can write next articles referring to this article. I desire to read even more things about it!

  • Paul

    I hope I don’t have this virus I am going to the hospital to have it checked out tomorrow I pray to g-d its not me!


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