Prestigious doctor attributes antibiotic resistance to “development” rather than “evolution”

On the Public Broadcasting System news last night, reporter Gwen Ifill did a six-minute interview with Dr. Michael Bell, a deputy director at Atlanta’s renowned Center for Disease Control and an infectious disease specialist. The topic was antibiotic-resistant microbes. Bell clearly discussed the problem and origin of these resistant “superbugs”, but one aspect of his interview bothered me and my undergraduate advisor Bruce Grant. That was Bell’s use of the word “developing resistance” instead of “evolving resistance” (see his statements at 1:02, 2:28 and, a similar statement 4:36).

Now I’m not sure that this was a deliberate avoidance of the “e word”, but it’s clearly misleading to use the term “developing” resistance instead of “evolving resistance.” The former implies that organisms can somehow adapt physiologically to antibiotics. The latter, which is what really happens, is that some individual microbes have genes conferring resistance to antibiotics and those subpopulations leave more offspring than others, so that the population adapts genetically. Saying, as Bell does, that “the germs continue to develop new ways of getting around the antibiotics”, is thus ambiguous as well as misleading.

This distinction is important, for one of the big misconceptions about evolution is that it occurs by individuals changing physiologically rather than populations changing genetically. By using the term “development,” Bell avoids what I see as a valuable teaching moment—here we actually see evolution in action! But of course 40% of Americans adhere to young-earth creationism when it comes to human origins, though I suspect many of those might accept the notion of evolution in microbes. After all, that’s just “microevolution.” But it’s easier to avoid the whole issue by making antibiotic resistance seem similar to forming calluses on a well-used hand: a physiological response. (I recognize that the potential for forming calluses is based on evolved genes.)

I’m not sure if Bell’s avoidance of the term “evolution” is deliberate, but it is suspicious. Bruce, even more suspicious, sent me the following email (reproduced with permission):

I just watched a segment on PBS news about antibiotic resistance in superbugs. The expert was Dr. Michael Bell from the CDC. He was articulate and knew his subject well, no doubt. But he consistently used the word “developed” when he should have said “evolved.” He gave the impression that antibiotic resistance in bacteria is a developmental process rather than a product of natural selection. I have seen/heard others do this again and again. In some cases the speaker/writer doesn’t know any better, but this guy surely does. I am wondering if this avoidance of using the word evolution is deliberate. Might people like Dr. Bell worry that if they dared use the word evolution then the government will cut their funding? Unlike f- and n-words, evolution doesn’t even get an “e”: it gets a “d” for development. Political correctness, I wonder?

PS. I’d bet that if an investigative reporter took the time to search office memos or emails at the CDC they’d find a policy directive warning their spokespeople to avoid using the e-word.

Well, watch the video and judge for yourself:

There may be some who approve of Bell avoiding the “e word,” for hearing that would, they’d argue, turn off creationists to his medical message. To those people I say: “Grow up.” The truth is the truth, and we can’t continually cater to religious sensibilities under the misguided notion that this will help get our message across more effectively.


  1. GBJames
    Posted August 5, 2015 at 9:26 am | Permalink


  2. Dominic
    Posted August 5, 2015 at 9:28 am | Permalink

    Another Radio programme of relevance was on the BBC World Service last night – available as a download…
    What’s Behind the Anti-Vax Movement?
    “This July, it was reported that a woman from Washington State in the US had died of measles. It was the first measles death in the country in 12 years and comes after a huge spike in the number of cases of the disease. There is little doubt about what has caused the rise. The ‘anti-vax’ movement – activists who refuse vaccines believing them to be harmful to children – is vocal, vibrant and virulent. But with their claims proven time and again to be without any scientific basis, why are the ‘anti-vaxxers’ still going – and apparently growing?”

  3. sean
    Posted August 5, 2015 at 9:50 am | Permalink

    I listened to this on PBS and it gave the idea that bacteria “grow” a resistance, It could leave you thinking that by taking less antibiotics yourself, they would work better on yourself in the future.

    A dangerous message.

    • infiniteimprobabilit
      Posted August 6, 2015 at 1:52 am | Permalink

      Eh? I thought over-prescription / overuse of antibiotics was one of the causes of resistant bacteria evolving. Or am I worng?


      • Diane G.
        Posted August 6, 2015 at 11:50 pm | Permalink

        Yes, but that doesn’t contradict sean’s scenario–some listeners indeed might interpret the information the way he suggests.

        • infiniteimprobabilit
          Posted August 7, 2015 at 12:40 am | Permalink

          Just that I don’t regard the message as dangerous. By taking less (unnecessary) antibiotics yourself, there’s a better chance of [whatever disease you catch in the future] not being antibiotic-resistant.

          There are some people who demand antibiotics for every sniffle, farmers feed them to cows ffs. That’s the real danger, I believe.


  4. JohnE
    Posted August 5, 2015 at 9:51 am | Permalink

    It seems to me that whenever I see or hear a story in the mainstream media about antibiotic-resistant microbes, the microbes are invariably described as having “developed” a resistance to the antibiotics. Unfortunately, I think that phrase has very much become part of the vernacular, such that I wouldn’t necessarily conclude that Dr. Bell had some sort of accomodationist agenda in using the term (although, of course, he might have). That said, I wholeheartedly agree that the cause of public science education would be much better served if the word “evolved” were used instead of “developed.”

    • Heather Hastie
      Posted August 5, 2015 at 2:16 pm | Permalink

      That’s pretty much my opinion – there’s little or no resistance to the “e” word in New Zealand, but “developed” is routinely used here too. I think it would be better to use “evolved” as I think that would actually help people to recognize the seriousness of the situation.

      The thing that annoys me the most about this whole situation is that it came about because of the cavalier attitude of many in the prescribing of antibiotics, and even worse, the failure of many health professionals to adhere to even basic infection control procedures like hand washing/cleansing consistently.

    • Diane G.
      Posted August 6, 2015 at 11:52 pm | Permalink

      Agree that “develop resistance” is the common vernacular for the phenomenon; we who are aware, though, could make an effort to remember to use the more exact word.

  5. Anonymous
    Posted August 5, 2015 at 9:56 am | Permalink

    Even if the journalist does not have the knowledge/education to know how this resistance to antibiotics occurs — a good journalist should ask the next question. That would be, how do these super bugs develop this resistance. If the doctor does not then discuss the evolutionary process that causes the resistance, then he is really avoiding the facts.

    • Posted August 5, 2015 at 9:57 am | Permalink

      Please don’t post as “Anonymous” in the future, as we can’t tell one “anonymous” from another. Use a pseudonym if you don’t want to use your real name. Thanks!

      • Randy Schenck
        Posted August 5, 2015 at 10:10 am | Permalink

        That was me and I do not use anonymous ever. The name and email are normally already entered but apparently for this comment is was not. The system is putting Anonymous in there, not me.

        • Heather Hastie
          Posted August 5, 2015 at 2:18 pm | Permalink

          WordPress has been doing some funny things with comments in the last few weeks – I’ve noticed it on my own site. There was an update yesterday that I hoped might help, but perhaps not.

          • Randy Schenck
            Posted August 5, 2015 at 10:08 pm | Permalink

            I was going to remove the name and email and try to post a comment to see if it happened again but decided not a good idea.

            I believe the system is suppose to say something like no name or email given and then not posted.

        • Diane G.
          Posted August 6, 2015 at 11:57 pm | Permalink

          It has happened a lot lately, Randy.

          Perhaps people complained after typing a longish comment, only to have it vanish when they hit post; only realizing subsequently that for some reason their name & eddress had been missing. So what used to be our problem is now Jerry’s. Hopefully the next update will politely remind one to re-enter the info if it’s gone. WP evolves very slowly, computer-age-wise.

  6. Scott M Moody
    Posted August 5, 2015 at 9:57 am | Permalink

    This has driven me crazy for the many years that I have taught Introduction to Biology both non-majors and majors (separate courses) at Ohio University. Thanks for posting; accurate vocabulary is extremely important.

  7. Posted August 5, 2015 at 9:59 am | Permalink

    There seems to be a trend among Creationists to call evolution “devopment” — now that the internet seems to make it hard for them to contain the evidence. Here is a video by Potholer who found out, three years ago, that Kent Hovind almost comes around, except for the nomenclature.

    Potholer and Hovind Come Together (Not like that!)

    • Posted August 5, 2015 at 10:01 am | Permalink

      Creationists didn’t steal a few letters, just a typo, “development” of course.

      • Heather Hastie
        Posted August 5, 2015 at 2:24 pm | Permalink

        It’s like their admission that “microevolution” exists, but not “macroevolution”. Until a pig gives birth to a puppy, they’ll insist evolution is a lie.

  8. Ken Pidcock
    Posted August 5, 2015 at 10:25 am | Permalink

    Very interesting observation. My first reaction was to dismiss the concern outright, and I went looking for CDC communications in which the evolution of drug resistance is discussed. They talk about resistance emerging, and about selective pressure, so you or I reading this stuff might never notice that they aren’t using the word evolve. Since academic scientists in the field frequently refer to the evolution of resistance, this does seem sketchy.

    • Diane G.
      Posted August 7, 2015 at 12:02 am | Permalink

      I suspect the CDC has to tiptoe around a lot of subjects to get funding to study them at all. Inevitable political restriction.

      Just yesterday I was reading an article asking why the CDC still wasn’t studying gun violence, even though the ban against it doing so had been lifted a few years ago. The answer was essentially the argumentum ad hot potato. Um.

  9. Rob
    Posted August 5, 2015 at 10:35 am | Permalink

    Interesting post. I’m really glad you brought this up. Good points made.

  10. John
    Posted August 5, 2015 at 10:37 am | Permalink

    In light of the Koch’s previous meddling in PBS content it is at least suspicious…

  11. KD33
    Posted August 5, 2015 at 10:40 am | Permalink

    I work on the periphery of microbiology and antibiotic susceptibility, and I wouldn’t make too much of this. All microbiologists and the vast majority of clinicians working on antibiotic resistance are fully aware of evolution as the underlying mechanism, but rarely use a sentence like “we’re seeing Klebsiella evolving resistance to gentamicin in the municipal hospital” or some such. “Develop” is the usual verb I’ve heard/seen, and I think it’s because they are usually concerned with what environmental factor may be causing resistance (e.g, overprescription of a particular antibiotic, horizontal propagation through a hospital that is not properly disinfecting, etc.) Also, a minor point: there are some strains that “switch on” resistance within the life span of a single bug. That is, a culture exposed to an antibiotic will for a few hours have its growth/cell cycle interrupted, but not die outright. After a time, which can be longer than its typical cell cycle, a bug can “switch on” a resistance gene and/or express a protective protein and resume its growth. Not really germane to the topic, but interesting (and a pain for those of us trying to assess resistance quickly).

    • Michael Finfer, MD
      Posted August 5, 2015 at 10:55 am | Permalink

      The same for physicians. They never use the word evolve, they use develop. I have to force myself to use the word evolve because develop is so ingrained by my training.

      Courses about evolution either need to be added to the medical school curriculum or they need to be added to undergrad requirements for admission. I think that many physicians are seriously lacking knowledge in the topic, and it is often an important public health issue, such as with regard to antibiotic resistance.

      • Gordon
        Posted August 5, 2015 at 4:51 pm | Permalink

        They are not there already! You make me wonder what else is not covered.

  12. eric
    Posted August 5, 2015 at 10:40 am | Permalink

    His remarks sound practiced and like he chose simplistic words and concepts on purpose. So I would say yes he probably intentionally chose (example) “become resistant” rather than “evolve resistance,” but no this was not because of creationists or creationism; mentions of evolution were simply one of the several casualties of the KISS principle applied to public speaking.

    • Curt Nelson
      Posted August 5, 2015 at 11:16 am | Permalink

      But the word “evolve” is simple. I think it’s a clear case of avoiding “evolve” for political reasons.

      • eric
        Posted August 5, 2015 at 12:19 pm | Permalink

        I would argue that you’re wrong, ‘become’ is a conceptually simpler word than ‘evolve.’ ‘Evolve’ involves the notions of change over generations, natural selection, differential reproductive success, and so on. ‘Become’ the way he’s using it just means “it was one way, now its another.”

        Now, we can argue separately about the wisdom of dumbing down our public science speech. Maybe the right thing to do was to go with the more complex concept. Stretch the public’s brains rather than kowtowing to the (expected) low reading comprehension level of your viewing audience. But that argument aside, I don’t see his word choice as a choice to avoid evolution per se. I see it more as part of his general strategy of keeping all of his answers to as low a reading comprehension level as was reasonably feasible.

        • Diane G.
          Posted August 7, 2015 at 12:09 am | Permalink

          “‘Evolve’ involves the notions of change over generations, natural selection, differential reproductive success, and so on.”

          I suspect for many it doesn’t even have those connections; rather, some will have extremely mistaken ideas, some will only recognize it in a vague way, and for some it’s just a “bad word.”

          I.e, I agree with the KISS hypothesis.

  13. Emerson Schmidt
    Posted August 5, 2015 at 10:41 am | Permalink

    Thinks are even worst. Once people acknowledge that labors in CDC use linguistic tricks in their interviews, one start to ask how often does it happens and whether it is a normal way to deal with the public in general.

    • eric
      Posted August 5, 2015 at 12:24 pm | Permalink

      It probably happens every single time a government representative speaks to the public. Official speech is not like personal speech, people rarely just wing it.

  14. Posted August 5, 2015 at 10:45 am | Permalink

    Using words judiciously and as correctly as possible is important! Esp.: Einstein’s and Hawking’s references to “God”, etc.

  15. Steve Gerrard
    Posted August 5, 2015 at 11:07 am | Permalink

    I hear this sort of phrasing all the time, which of course doesn’t make it okay.

    “Tuna fish in the antarctic developed anti-freeze in their blood to survive in the cold.” Except that most of them just died, and only a few with a little bit of anti-freeze survived, and then those with a little more, until over time a population of cold tolerant tuna evolved.

    It seems to be a common short hand, one that unfortunately is often misleading.

  16. Joseph DeSisto
    Posted August 5, 2015 at 11:10 am | Permalink

    Using the word “development” is misleading, but if the CDC’s aim is to prevent disease, then catering to a less-educated audience by avoiding the “e-word” might be a sacrifice worth making. There are parts of the country where the word “evolution” is enough for someone to tune out everything else you are saying. It’s important to teach the facts about evolution, but it’s probably more important to prevent antibiotic-resistant diseases from evolving.

  17. Torbjörn Larsson, OM
    Posted August 5, 2015 at 11:17 am | Permalink

    Not that it is a large problem here in Sweden, but we simply have no differentiating term between evolve and develop. Same has we have none between probability and likelihood I note, despite being different.

    And sometimes the difference counts. So I made up a verb for evolve (‘evolvera’) from a suitable verb template, and no one has had to ask what I mean. And just yesterday I saw a (government presentation!) where they had solved the language difficulty for likelihood in much the same manner (introduced the adverb [?] ‘trolighet’ from a suitable adverb template)!

    Sigh. I hear that on Iceland they do this on a regular basis, to avoid introducing ‘foreign’ english terms.

    • eric
      Posted August 5, 2015 at 12:35 pm | Permalink

      Heh I think the French try that too. Good luck to them, but I don’t think in the long run that it will work.

      Consider it karma: from the 6 or 700s through the 1800s English stole and incorporated words from every language around it. Now in the 1900s and 2000s, we’re just giving all the other languages some words back. 🙂

      • TJR
        Posted August 5, 2015 at 1:17 pm | Permalink

        English is the de facto lingua franca, thus giving carte blanche for any ad hoc lending or borrowing.

        • rickflick
          Posted August 5, 2015 at 4:01 pm | Permalink

          bene totaliter!

          • merilee
            Posted August 5, 2015 at 11:21 pm | Permalink

            Just been watching the Danish series “Borgen”, with subtitles, of course. It’s interesting how many English phrases are injected into the Danish. “Spin doctor” makes sense, but “fifteen minutes of fame”??

          • merilee
            Posted August 5, 2015 at 11:23 pm | Permalink

            which translates to Totes amazeballs?

    • TJR
      Posted August 5, 2015 at 1:14 pm | Permalink

      Not having separate words for probability and likelihood must make statistics very difficult in Swedish.

      • Gregory Kusnick
        Posted August 5, 2015 at 1:20 pm | Permalink

        Many years ago I assisted a Swedish engineer in translating a computer manual. One of the problems we ran into was trying to find distinct Swedish words for “separator” and “delimiter”.

        • Posted August 5, 2015 at 8:42 pm | Permalink

          Now there’s a subtle distinction if there ever was one. After reading your comment, I couldn’t come up with a significant distinction between separator and delimiter in computing. I then went to Google and it was of little help either. What do you see as the distinction? The only subtle case I can see is something like the following strings using a space as a separator versus as a delimiter: “one two three”, “one two three “. In the latter, the final space is required to indicate “three” is terminated. In practice, an algorithm would render the final space optional to avoid buffer overflow. In any case, I can’t imagine separator and delimiter meaning different things in everyday discussion.

          • Gregory Kusnick
            Posted August 5, 2015 at 8:54 pm | Permalink

            As I recall, this particular case involved bracketed lists of some sort, e.g. [a,b,c]. The brackets delimit (mark the boundaries of) the entire list, while the commas separate list elements.

            In retrospect, we probably should have designed a better UI that didn’t depend on such subtleties of text parsing.

            • Diane G.
              Posted August 7, 2015 at 12:15 am | Permalink

              Tho once you explain it with an example like that it makes perfect sense!

            • Posted August 7, 2015 at 1:01 pm | Permalink

              With something like the strtok function in C, you pass the string and the delimiter list and it parses it into tokens based on the delimiters, though you’d need something slightly more complicated to account for matching ‘[‘ and ‘]’. You could do two passes, calling the brackets delimiters on the first pass, giving you back a set of bracketed lists and then parse the individual lists with ‘,’ as a delimiter. Or roll a one pass function that does both at once.

              Even Wikipedia uses delimiter and separator somewhat interchangeably, though I agree with you that in English your example is probably a bit less ambiguous if the comma is called a separator and the brackets delimiters. But list delimiter and token delimiter seems clear enough as well.

  18. squidmaster
    Posted August 5, 2015 at 11:23 am | Permalink

    I’m a physician/neuroscientist and I work at a tertiary care medical center. There is constant discussion of antibiotic resistant bacteria. By far the most common term used to describe the evolution of antibiotic resistance is ‘develop’. As a previous poster noted, the term ’emerge’ is also used to describe the appearance of antibiotic resistance in populations of organisms exposed to the drugs. The word ‘evolve’ is also used, but less frequently, although presentations of academic research are clear that acquisition of resistance occurs through evolution, that is, selection of resistant strains.

    The fundamental importance of evolution as an explanatory model for myriad observations in medicine is wholeheartedly embraced by over 90% of my colleagues. I’ve run across a few academic docs who were deniers or outright creationsists, but they are in the clear minority.

    I’ve done a quickie pub med search for ‘antibiotic resistance’ and ‘development’ which turned up 3407 articles and ‘a.. res..’ and ‘evolution’ which turned up 1568 articles. I skimmed the titles of the first hundred or so papers in each list and noticed that the ‘development’ list contained more clinical science and the ‘evolution’ list contained more basic science. What was really interesting was that, when I compared the first 200 hits (roughly, the 200 most recent articles) in each search, there were only 11 articles that appeared in both lists.

    This suggests (based on some back of the envelope methods) that there is highly divergent usage of the terms ‘development’ and ‘evolution’ to explain the acquisition and selection for antibiotic resistant strains of bacteria. I suspect that some of this reflects historical accident evolving (as it were) into tradition. Whether there is a more pernicious avoidance of ‘evolution’ at the national policy/education level is less clear.

    And now, I have to go back to writing grants, or my funding portfolio will suffer extinction.

  19. Aaron Siek
    Posted August 5, 2015 at 12:07 pm | Permalink

    Along with several others above, I doubt there is any malicious or accomodationist intent in Dr. Bell’s usage. I’ve spent my entire professional career in clinical research (mostly in oncology, but have also done some work with antibiotics), and physicians routinely use “develop” in this context, even though they know the evolutionary mechanisms in play. I think it’s just a term of art, now, established in the culture. Having grown so used to its use by physicians participating in clinical research — I don’t think I’ve ever heard “the microbes evolve resistance”, it’s always “develop” — I wouldn’t have batted an eye at the phrase. My brain automatically knows that “develop” means “evolve” in this context. Perhaps you’re right that it would be preferable if folks used the e-word and avoided the d-word, but it will probably be quite a challenge to effect the change with the term “develop” so deeply embedded in the culture. I’ll try to do my part!

  20. merilee
    Posted August 5, 2015 at 12:11 pm | Permalink

    I watched that segment last night, and though I didn’t notice his avoidance of the e-word, it did sound as if he was talking to a bunch of junior high kids and I kind of tuned out what he was saying…

    • eric
      Posted August 5, 2015 at 12:37 pm | Permalink

      Yes exactly my thought. He’s fine tuned his speech to keep everything simple. Explicit mentions of evolution was a casualty of that but not the focus of it.

  21. Posted August 5, 2015 at 12:25 pm | Permalink

    I agree with several of the comments above that the problem is often stated this way, say in popular speak, and there is not some underlying theoretical agenda being driven in most of those cases. On the flat of it, I think many people are just saying this system is arriving at (developing) the ability to avoid antibacterial agents.

    However, with all that said, the video was strange. I think he was deliberately avoiding the word evolve, given the lengthy explanation and ample opportunity where the word evolve was most appropriate. Someone needs to hit our government officials over the head.

    I would say more than grow up, this should be basic educational necessity for every last individual. One does not understand the beginning of this problem unless they understand a modicum of the evolutionary structure of the problem. The explanation that he was trying to give requires basic evolutionary processes. I suppose, and we probably are all guilty of this at some time, some people could think, “I don’t have a clue what that man is saying, but he sounds smart and he has told me that if I wash my hands we will all get less sick.”

    But surely we can do better that. At least at a broader level, people of the 21st century should understand how this antibacterial problem is developing.

  22. Pliny the in Between
    Posted August 5, 2015 at 12:56 pm | Permalink

    I agree with the above comments from the healthcare sector.

    I do think that the overwhelming majority of physicians fully embrace evolution while not using precise terminology.

    But like the issue of using the phase ‘keeping the brain dead alive with machines’, the term development is not only wrong but it reinforces the misconception that evolution is in any way goal directed.

  23. Gregory Kusnick
    Posted August 5, 2015 at 1:16 pm | Permalink

    When speaking of drug resistance in humans, it’s normal and appropriate to say that such resistance “develops”. Perhaps that explains the ingrained use of “develop” for drug resistance in microbes. There’s a sort of unconscious analogy that views the microbe population as a unitary superorganism that “develops” resistance, rather than a collection of individuals that evolve it by natural selection.

    It’s also worth noting that the human immune system employs Darwinian processes of variation and selection to generate antibodies, but we wouldn’t say that an individual human “evolved” an immunity, even though that’s in some sense what happened.

    Similarly, some tumors are arguably instances of natural selection among somatic cells, in which mutant cells outcompete normal cells for resources. But again, a tumor doesn’t “evolve”, it “develops”.

    So there’s ample precedent for using “develop” in situations involving selection of genetic variants.

  24. Posted August 6, 2015 at 11:16 am | Permalink

    A 2007 paper in PLoS Biology shows that this is a widespread problem in the medical literature: “Evolution by Any Other Name: Antibiotic Resistance and Avoidance of the E-Word.” Open access link:

    • Gregory Kusnick
      Posted August 6, 2015 at 12:26 pm | Permalink

      “Avoidance of the E-Word” seems a bit misleading given that “we found no evidence that deliberate efforts were being made by medical researchers to deny that evolutionary processes were involved in the increase of antibiotic resistance.”

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