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Science Forum Index » Bio Evolution Forum » Paper: Evolution by Any Other Name - Antibiotic Resistance a
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| Robert Karl Stonjek |
 Posted: Wed Feb 14, 2007 8:49 am |
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Essays articulate a specific perspective on a topic of broad interest to
scientists.
Evolution by Any Other Name: Antibiotic Resistance and Avoidance of the
E-Word
Janis Antonovics*, Jessica L. Abbate, Christi Howell Baker, Douglas Daley,
Michael E. Hood, Christina E. Jenkins, Louise J. Johnson, James J. Murray,
Vijay Panjeti, Volker H. W. Rudolf, Dan Sloan, Joanna Vondrasek
Citation: Antonovics J, Abbate JL, Baker CH, Daley D, Hood ME, et al. (2007)
Evolution by Any Other Name: Antibiotic Resistance and Avoidance of the
E-Word. PLoS Biol 5(2): e30 doi:10.1371/journal.pbio.0050030
Published: February 13, 2007
Copyright: © 2007 Antonovics et al. This is an open-access article
distributed under the terms of the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any
medium, provided the original author and source are credited.
Janis Antonovics, Jessica L. Abbate, Christi Howell Baker, Douglas Daley,
Michael E. Hood, Christina E. Jenkins, Louise J. Johnson, James J. Murray,
Vijay Panjeti, Volker H. W. Rudolf, Dan Sloan, and Joanna Vondrasek are with
the Department of Biology, University of Virginia, Charlottesville,
Virginia, United States of America.
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The increase in resistance of human pathogens to antimicrobial agents is one
of the best-documented examples of evolution in action at the present time,
and because it has direct life-and-death consequences, it provides the
strongest rationale for teaching evolutionary biology as a rigorous science
in high school biology curricula, universities, and medical schools. In
spite of the importance of antimicrobial resistance, we show that the actual
word "evolution" is rarely used in the papers describing this research.
Instead, antimicrobial resistance is said to "emerge," "arise," or "spread"
rather than "evolve." Moreover, we show that the failure to use the word
"evolution" by the scientific community may have a direct impact on the
public perception of the importance of evolutionary biology in our everyday
lives.
To establish whether the word "evolution" is used with different frequency
by evolutionary biologists versus researchers in the medical fields, we
searched scientific journals published since 2000 for research papers and
reviews dealing with antimicrobial resistance. To find these papers, we used
standard search engines and databases to identify papers with "antimicrobial
resistance" or "antibiotic resistance" (or with names of specific
antibiotics) in the titles or abstract. We deliberately did not include the
word "evolution" in the searches, so as not to bias our findings in favor of
articles with this word. However, we chose for further analysis only those
articles that were obviously describing the evolution of antimicrobial
resistance, and excluded those that described, for example, the biochemical
basis of resistance or the pharmacology of antimicrobial agents. The
articles were chosen in an unbiased manner by several readers who each
independently read the first papers they found that met these criteria. We
compared 15 articles that were primarily published in evolutionary journals
(such as Evolution, Genetics, and Proceedings of the Royal Society of London
Series B) with 15 articles that were published in primarily medical journals
(such as The Lancet, The New England Journal of Medicine, and The Journal of
Antimicrobial Chemotherapy). (A list of the papers and articles that are the
basis of the results reported here is available in Text S1.)
Each reader then read the articles in their entirety. In each paper we
explicitly noted and counted the words or phrases (see below) that were used
to describe the evolutionary process, in order to obtain the proportion of
times that the actual word "evolution" (or its lexemes such as
"evolutionary" or "evolving") was used when reference was being made to the
evolutionary process. Although we deliberately read equal numbers of
articles in the two types of journals, we actually found that by far the
majority of publications on the evolution of antibiotic resistance are in
the medical field, and not in academic evolutionary biology or genetics
journals. The evolution of antibiotic resistance, while critically important
from a medical viewpoint, is no longer in and of itself a novel finding in
evolutionary biology.
The results of our survey showed a huge disparity in word use between the
evolutionary biology and biomedical research literature (Figure 1). In
research reports in journals with primarily evolutionary or genetic content,
the word "evolution" was used 65.8% of the time to describe evolutionary
processes (range 10%-94%, mode 50%-60%, from a total of 632 phrases
referring to evolution). However, in research reports in the biomedical
literature, the word "evolution" was used only 2.7% of the time (range
0%-75%, mode 0%-10%, from a total of 292 phrases referring to evolution), a
highly significant difference (chi-square, p < 0.001). Indeed, whereas all
the articles in the evolutionary genetics journals used the word
"evolution," ten out of 15 of the articles in the biomedical literature
failed to do so completely. Instead, 60.0% of the time antimicrobial
resistance was described as "emerging," "spreading," or "increasing" (range
0%-86%, mode 30%-40%); in contrast, these words were used only 7.5% of the
time in the evolutionary literature (range 0%-25%, mode 0%-10%). Other
nontechnical words describing the evolutionary process included "develop,"
"acquire," "appear," "trend," "become common," "improve," and "arise."
Inclusion of technical words relating to evolution (e.g., "selection,"
"differential fitness," "genetic change," or "adaptation") did not
substantially alter the picture: in evolutionary journals, evolution-related
words were used 79.1% of the time that there was an opportunity to use them
(range 26%-98%, mode 50%-60%), whereas in biomedical journals they were used
only 17.8% of the time (range 0%-92%, mode 0%-10%).
Figure 1. Frequency of Use of Words to Describe the Evolutionary Process in
Evolutionary Journals versus Biomedical Journals
The left-hand pair of bars show percentage use of the word "evolution," and
the right-hand pair of bars show percentage use of the words "emerge,"
"arise," or "increase." Data shown are unweighted means and standard errors,
based on 15 papers in evolution or genetics journals and 15 papers in
biomedical journals.
In spite of the disparity in word use, we found that the papers in the
medical literature generally included professional and competent
descriptions of evolutionary processes. At times words such as "develop" or
"acquire" did creep in, but egregiously misleading phrases were relatively
rare. For example, once we found the wording "bacteria had learned to resist
antibiotics" and at another time "the activity of antimicrobial agents had
decreased" (which, if read literally, implies that the antimicrobials
themselves were changing rather than that the pathogens were evolving). But
these were exceptions.
In reading these papers, 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. The frequent use of the
term "emergence" rather than "evolution" seemed more to be the result of a
simplified phraseology that has "emerged and spread" out of habit and
repeated usage. It may also be that many nonprofessional evolutionary
biologists consider "evolution" to be a rather nonspecific word meaning
"gradual change," and that "emergence" more explicitly incorporates the
component aspects of the evolutionary process, namely, mutation,
recombination, and/or horizontal transfer of resistance. The word "spread"
may, similarly, appear to incorporate the component processes of
transmission, horizontal transfer, and increase in allele frequency. While
these processes are recognized by professional evolutionary biologists as
important aspects of evolutionary change, biomedical researchers may have
the sense that the word "evolution" is itself too imprecise. Indeed,
evolutionary biologists are sometimes accused of focusing too much attention
on "change in gene frequency" rather than on the origin of variants by
mutation and recombination, or on the consequences of changes in allele
frequency for numerical abundance and distribution.
There is also the possibility that the failure to use the word "evolution"
may reflect the mistaken sense that evolution implies processes that are
long past, slow, and imperceptible. This is more worrying, as it fails to
acknowledge the importance of evolution as a powerful force in present-day
populations of all organisms, and not only microbes.
A critical question is whether avoidance of the word "evolution" has had an
impact on the public perception of science. To investigate this, we examined
whether the use of the term "evolution" in the scientific literature affects
the use of this word in the popular press, i.e., whether there is evidence
for "cultural inheritance" of word use. We searched articles on
antimicrobial resistance in national media outlets, such as The New York
Times, The Washington Post, Fox News, and the BBC (Text S1). Our results
showed that the proportion of times the word "evolution" was used in a
popular article was highly correlated with how often it was used in the
original scientific paper to which the popular article referred (Figure 2).
This clearly shows that the public is more likely to be exposed to the idea
of evolution and its real-world consequences if the word "evolution" is also
being used in the technical literature.
Figure 2. Use of "Evolution" in Popular Articles Based on Research Papers
This graph shows the relationship between the frequency of use of the word
"evolution" in popular press articles addressing antimicrobial resistance
and the frequency of its use in the corresponding research article. Most of
the articles included were in the biomedical literature (Text S1). The point
at the origin represents nine pairs for which "evolution" was mentioned
neither in the scientific nor in the popular version. The regression is
highly significant (d.f. = 21, p < 0.0001, ß = 0.76; weighted arcsine square
root transformed; points and fitted line in figure represent untransformed
data).
We wondered whether these patterns were changing, so we carried out a survey
of the use of the word "evolution" from 1991 to 2005 in the titles and
abstracts of papers published in 14 scientific journals, as well as in the
titles of proposals funded by both the US National Science Foundation
(Division of Environmental Biology) and the US National Institutes of Health
(National Institute of General Medical Sciences). The results showed that
the use of the word "evolution" was actually increasing in all fields of
biology, with the greatest relative increases in the areas of general
science and medicine (Figure 3). This reflects the growing importance of
evolutionary concepts in the biomedical field, and highlights even more the
strange rarity with which the word "evolution" is used in the biomedical
literature dealing with antimicrobial resistance. It has been repeatedly
rumored (and reiterated by one of the reviewers of this article) that both
the National Institutes of Health and the National Science Foundation have
in the past actively discouraged the use of the word "evolution" in titles
or abstracts of proposals so as to avoid controversy. Indeed, we were told
by one researcher that in the title of one proposal, the authors were urged
to change the phrase "the evolution of sex" to the more arcanely eloquent
wording "the advantage of bi-parental genomic recombination."
Figure 3. Change over Time in the Frequency of Use of the Word "Evolution"
in Journals and Grant Proposals
This figure shows change in the frequency of use of the word "evolution" in
(A) paper titles and abstracts for journals classified by type and (B)
titles of funded research proposals classified by US federal granting
agency. Note that the data for general science journals and medical journals
are shown at 10 and 100 times their values, respectively. Analysis of
covariance (log of arcsine square root transformed data) showed that the
rate of increase of use of the word "evolution" was significantly greater in
the journal categories of general science and medical than in the
evolutionary category (p < 0.002). Journal classification was as follows:
evolutionary journals: Evolution, Genetics, Heredity, Journal of
Evolutionary Biology, Journal of Molecular Evolution, Molecular Biology and
Evolution; general science journals: Nature, Nature Genetics, and Science;
medical journals: BMJ, Clinical Infectious Diseases, JAMA, The Lancet, and
The New England Journal of Medicine. Funding data are from the online data
retrieval systems of the National Science Foundation (Division of
Environmental Biology) (NSF [DEB]) and National Institutes of Health
(National Institute of General Medical Sciences) (NIH [GMS]).
Nowadays, medical researchers are increasingly realizing that evolutionary
processes are involved in immediate threats associated with not only
antibiotic resistance but also emerging diseases [1,2]. The evolution of
antimicrobial resistance has resulted in 2- to 3-fold increases in mortality
of hospitalized patients, has increased the length of hospital stays, and
has dramatically increased the costs of treatment [3,4]. It is doubtful that
the theory of gravity (a force that can neither be seen nor touched, and for
which physicists have no agreed upon explanation) would be so readily
accepted by the public were it not for the fact that ignoring it can have
lethal results. This brief survey shows that by explicitly using
evolutionary terminology, biomedical researchers could greatly help convey
to the layperson that evolution is not a topic to be innocuously relegated
to the armchair confines of political or religious debate. Like gravity,
evolution is an everyday process that directly impacts our health and
well-being, and promoting rather than obscuring this fact should be an
essential activity of all researchers.
Source: PLoS Biology [Open Access]
http://biology.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pbio.0050030
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