Antibiotic resistance: The non-Darwin truth
|January 8, 2012||Posted by News under Culture, Darwinism, News|
In “Evolutionary Lessons From Superbugs” (Huffington Post, January 8, 2012), James Shapiro, author of Evolution: A View from the 21st Century (FT Press Science), talks about how Darwinism misled scientists who were trying to understand antibiotic resistance:
In the early days of molecular biology, bacterial geneticists applied conventional evolutionary concepts from the pre-DNA period to explain the evolution of antibiotic resistance. The theory was that mutations could alter the structure of cell components and either block entry of the drugs into the bacteria or prevent their action on cellular targets, such as the enzymes essential to cell wall synthesis. Even if the initial mutation did not confer a high degree of resistance, accumulation of several sequential changes would result in resistance to the antibiotic levels used in clinical medicine. Indeed, a wide variety of laboratory experiments confirmed this theory, and bacterial geneticists isolated the predicted mutant strains. In virtually all cases, the resistant mutants grew less well than the parental sensitive bacteria, leading to the comforting conclusion that resistant bacteria would not significantly accumulate in nature. The degree of confidence was so great that the U.S. Surgeon General in 1967 declared that “the war against infectious diseases has been won” (Fauci 2001).
There were problems both with the science and the new public health policy based on it. The Surgeon General “misunderestimated” the bacteria, which followed their own evolutionary rules and did not listen to what the scientists said they should do. Although experimentally confirmed, the mutation theory of antibiotic resistance failed to account for most cases in the real world. Resistance continued to spread among bacteria isolated in clinics around the globe. Even more ominously, different strains of pathogenic bacteria increasingly displayed resistance to more than one antibiotic at a time. Research pioneered in Japan found that multiple antibiotic resistances could be transferred simultaneously from one bacterial species to another (Watanabe 1967). The DNA agents responsible for this transfer are circular molecules that are called multidrug resistance plasmids, which can move from one cell to another (Clowes 1973; Novick 1980). Moreover, the resultant multiply resistant bacteria were not altered in their cellular structures or inhibited in their growth properties. Rather, they had acquired new biochemical activities that could destroy or inactivate the antibiotics, chemically alter their targets, or remove them from the bacterial cell (Davies 1979; Levy 1998).
Multiple antibiotic resistance clearly represented genome change and evolution of a type unimagined in the pre-DNA period. DNA molecules could be transferred “horizontally” between unrelated cells rather than inherited from ancestral cells. Moreover, horizontally transferred DNA could carry complex sets of genetic information encoding multiple distinct biochemical activities. Evolutionary leaps involving several characteristics at once could occur through horizontal DNA transfer.
We wonder how many people out there took the long walk out of research just for saying what they knew, and how many others just kept quiet.
And the dull-witted docent went on telling the public that antibiotic resistance proves that Darwin was right.
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