Superbugs swap resistance genes16th December 2010
Bacterial species around the world have already begun using a gene-sharing mechanism that will allow them to incorporate drug resistances from unrelated bacterial strains, according to recent US research.
The string of genes involved is known as a transmissible genetic element, and in this case, the transmissible genetic element being passed around is known as New Delhi metallobeta-lactamase 1 (NDM-1).
NDM-1 contains genes that code for an enzyme capable of digesting almost every antibiotic in existence.
While doctors have known of the existence of NDM-1 for several years already, it is only recently that superbugs derived from NDM-1 have started to appear in hospitals.
Several months ago, travellers to the Indian subcontinent suffered infections that led doctors to believe NDM-1 was already well-established in New Delhi and had spread to the rest of India, Bangladesh, Pakistan, and the UK.
Study author Robert Moellering, of Harvard Medical School and Beth Israel Deaconess Medical Center in Boston said that the enzyme was frightening.
Bacteria are particularly adept at sharing genes between species, and Moellering said that NDM-1 had already been found in bacterial strains in the United States, Israel, Turkey, China, India, Australia, France, Japan, Kenya, Singapore, Taiwan, and the Nordic countries.
Common bacteria like E coli now routinely incorporate NDM-1 in their genomes, meaning that whenever these species encounter an antibiotic compound, they can call upon the enzyme to break down that antibiotic, as if it were a food.
Doctors have known about bacterial resistance for nearly 60 years now.
When penicillin was first introduced, researchers noted how its effectivity decreased over time.
At that time, doctors did not believe that science would ever bow to bacterial resistance, and researchers kept developing new antibiotics.
In the US, antibiotic resistance is now a factor in every hospital-related bacterial infection as well as in half of all bacterial infections overall.
And Chinese officials said recently that China's per capita consumption of antibiotics was 12 times the global average.
Moeller said that the latest generation of superbugs would cause headaches for future generations.
So far, the only drug the NDM-1 enzyme cannot digest, known as colistin, is also toxic to humans.
As for NDM-1 itself, Moeller said that nonprescription use of antibiotics in India was widespread.
He said that there were areas of the country where diarrhoeal diseases were prominent and people were crowded in close living quarters, creating an ideal breeding ground for the next generation of superbugs.
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Title: Superbugs swap resistance genes
Author: Luisetta Mudie
Article Id: 17073
Date Added: 16th Dec 2010