Chat with Maryn McKenna about antibiotic resistance today


Maryn McKenna—my favorite "Scary Disease Girl" and author of Superbug—will be taking questions during a live chat today at Scientific American's Facebook page. The chat starts at 2:00 Eastern and lasts for a half-hour.

The chat is connected to a new article that Maryn wrote for Scientific American, which centers around some disturbing new trends in antibiotic resistance. You may have heard about the recently announced discovery of a pneumonia-causing bacteria, called Klebsiella pneumoniae, that had developed a resistance to a class of antibiotics called carbapenems. This is more than just another bacteria resistant to another antibiotic.

Carbapenems are the antibiotics of last resort. The end of the line before we literally run out of ways to treat bacterial disease. The fact that bacteria are growing resistant even to them would, alone, be concerning. But the type of bacteria involved also matters. A lot. Klebsiella pneumoniae is a gram-negative bacteria.

That designation, which borrows the name of a Danish 19th-century scientist, superficially indicates the response to a stain that illuminates the cell membrane. What it connotes is much more complex. Gram-negative bacteria are promiscuous: they easily exchange bits of DNA, so that a resistance gene that arises in Klebsiella, for example, quickly migrates to E. coli, Acinetobacter and other gram-negative species. (In contrast, resistance genes in gram-positives are more likely to cluster within species.)

Gram-negative germs are also harder to kill with antibiotics because they have a double-layered membrane that even powerful drugs struggle to penetrate and possess certain internal cellular defenses as well. In addition, fewer options exist for treating them. Pharmaceutical firms are making few new antibiotics of any type these days. Against the protean, stubborn gram-negatives, they have no new compounds in the pipeline at all. All told, this unlucky confluence of elements could easily export disaster from medical centers to the wider community.

Scientific American: The Enemy Within

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  1. I had no idea that the DNA helix was so large that you could see it like that!!! Wild stuff for sure.

    1. I had no idea that the DNA helix was so large that you could see it like that!!! Wild stuff for sure.

      That illustration is very much artistic license, and very, very misleading; in reality, the DNA is many hundreds of times narrower than the chromosome, being very tightly folded and structured on many levels.

      Unless you are being sarcastic, in which case: agreed.

  2. Also that’s a Eukaryotic chromosome, ie. not the type found in DNA. Bacterial DNA is thin and circular

    1. That is a eukaryotic chromosome in the picture, yes, but it isn’t true that all bacterial chromosomes are circular, although that’s a common misconception. Some are, some aren’t (Borrelia‘s for example is linear). E. coli‘s chromosome is circular, and many textbooks overgeneralize and assume all bacteria are like E. coli.

  3. Should we blame lazy genetic engineering practices? Using anti-biotic resistance as a litmus test for the intake of new DNA means inserting genes for anti-biotic resistance into more and more species of plants around the world. Could this be related? If so,

    Thanks, Monsanto.

  4. Although these things are very scary, there is a whole second tier to these Resistance issues that avoid the mass media.

    Many of the animal based foods we eat have huge parisite problems, and most of the chemicals available are becoming less and less effective (killing all but the most resistant bugs can do that!)

    Basically, if we cant get our parasite issues under control in those animals, we wont be eating them anymore.

    Those animals include, beef, sheep, goats, chickens, turkeys…

    so start hoarding vegetarian recipes if you live through the superbug.

  5. It is very hard to tell a patient your not giving them an antibiotic for their ear ache or cough. Especialy if they just spent 2 hours waiting to see you. Mom’s are the worst, I’ve lost many patients because “Dr. such and such always gives us antibiotics”.

  6. So this might be a good time to ask: how is development going on drugs based on interfering with bacterial quorum sensing?

  7. It seems to me that, in the absence of effective antibiotic treatments, we’re going to have to start taking hygiene in the hospital setting a lot more seriously.

    Imagine what will happen to medical costs when everything that goes into the body – including expensive electronic gear like endoscopes – has to be thought of as single-use, to be taken out of sterile packaging and then tossed. The article specifically mentions some cases of infection via endoscopes. What if hospital rooms have to start looking more like clean rooms, with dedicated air handling units, steel and nonporous ceramic surfaces built to be sterilized, single-use disposable mattresses that head straight to the incinerator when you’re done with them, etc. Imagine the impact this will have on medical care in an era where the population’s demographics already strains resources.

    What’s much more likely to happen, if we return to the pre-antibiotic status quo, is that invasive medical treatments will become less and less common, or just more and more likely to lead to death. Bad heart? Sure, we’ll operate, but you’ll probably die anyway. Broken hip? It’s going to stay broken. Scarier still is the example the article mentions: minor things like urinary tract infections progressing unchecked and resulting in death.

    Here’s hoping that genetic engineering can create custom viruses that target bacteria with sufficient selectivity and efficacy to keep that from becoming our reality again. In the mean time, if the private sector has failed to allocate sufficient resources to the war on infectious disease, then the government should step in. If we can have government-funded weapons development, why can’t we have a taxpayer funded drug laboratory?

    1. Single use medicine will be great for the investors! Think of all the money to be made. Time to invest in healthcare, and plastics.

      Or maybe medicine will look a lot more like it did a few decades ago when everything could go into the autoclave and be used again that afternoon or next day.

  8. We should be investing heavily in developing phage therapy ->

    A treatment guaranteed not to fail, as viruses reproduce faster than bacteria. But it takes a lot of time to build up banks of phages tailored to the various bugs out there, we should get onto it now, not once it’s already a serious problem.

    1. No technology is “guaranteed not to fail.” Clearly, when phage therapy fails, it will fail only in ways you don’t expect.

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