The ‘Klingons’ are gaining the upper hand.
Imagine: We’re locked in a struggle for survival against our age-old enemy, the Klingons. Increasingly resistant to our weapons, we now hear they have a new recruit—‘Gene,’ code name ‘MCR-1’—who has been travelling the planet dropping off a blueprint for a new weapon. The plan shows affiliated resistance groups how to build a device that disables anything we can throw at them thus rendering them virtually invincible. And just last week we learned that Gene has entered the United States. Captured at a military hospital in Pennsylvania, though not before he shared his weapons plan with at least one local resistance group, Gene is being interrogated at the Walter Reed Army Institute of Research. The key question: Who else has Gene given his blueprint to for making this new weapon?
The analogy refers to a study published last week about a bad bug, E coli, that was resistant to the last-resort antibiotic colistin and, the researchers fear, to all antibiotics: “The recent discovery of a … colistin-resistance gene, mcr-1, heralds the emergence of truly pan-drug resistant bacteria,” write the authors. Tom Frieden, MD, who runs the US Centers for Disease Control, calls this an alarming development that could mean “the end of the road” for antibiotics.
The study concerned a 49 year old woman at a military hospital in Pennsylvania being treated for an E coli-driven urinary tract infection. Her antibiotic therapy wasn’t working so the doctors sequenced the E coli genome to see if they could figure out why. It turns out that the E coli had recruited a brand new gene, mcr-1, that acts as a blueprint for making an enzyme that attacks and defeats any antibiotic thrown at it.
It’s the first known case of the gene appearing in the United States. Researchers at Walter Reed are studying the gene to see how to defeat it. Meanwhile, the discovery raises two urgent issues: How prevalent is the gene in the US and elsewhere; and, crucially, even if it’s not prevalent, will it become so because it spreads easily, like the common cold, say.
The gene has been found primarily in E coli, but has also been found in other members of the E coli family of bugs, such as Salmonella and Klebsiella pneumonia. These mcr-1 gene-containing pathogens have so far gotten into humans, animals, food, and environmental samples, on every continent, and have even been found in a hospital patient in Canada.
But the real problem is this: The gene has the ability to spread beyond the E coli family to all bacteria. That’s why people like Dr. Frieden are so concerned: the E coli became resistant to the antibiotics not through mutation, but by acquiring a roving snippet of DNA called a plasmid—a ‘taxi cab’ for genes— that carries the resistance-conferring mcr-1 gene. And just like taxis, these plasmids can quickly and easily deliver their gene passengers to their destination, in this case, to other bacteria.
Here’s the concerning scenario. Right now antibiotic-resistant bacteria kill at least 23,000 people in the US each year and seriously hurt two million more. What if this new mcr-1 gene infiltrates MRSA, say, that is already so ubiquitous in hospitals and, increasingly, in the community? What will the numbers be then?
One more thing. Our understanding of the world around us is increasingly being driven by the biological sciences, especially genetics (for example, the project announced yesterday to synthesize the Human Genome). In order to properly assess the disease risks we face, and to have intelligent, informed discussions about these risks, we have to find a way to keep up with this ever- expanding body of knowledge.
The following video is offered for that reason. It’s from the Open Access course at the University of British Columbia. They say it’s “all you really need to know about DNA, in 3 minutes.” Notice, for example, the difference between a chromosome, DNA, and a gene. Enjoy:
BBC Knowledge Explainer DNA from Territory on Vimeo.