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roundtable: the evolving enemy Watch Show 4:
"The Evolutionary Arms Race"
on PBS
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Select a question:
How concerned should we be about becoming infected with resistant bacteria from foods like chicken, beef, and even aqua-cultured fish that may have been grown on diets treated with antibiotics? Will eating less of these foods, perhaps by switching to "organic" chicken, reduce our risk, and do vegetarians have a reduced risk for this reason?
If the use of antibiotics in a widespread fashion at low doses in agriculture, particularly in the raising of animals, is so common and yet so potentially dangerous from the standpoint of evolution of resistance, why is it still the practice? What are the costs and benefits of this practice?
Several people have submitted questions not about antibiotics, but about all of the liquid soaps that are now for sale in supermarkets that are labeled "antibacterial." Do these work like antibiotics in causing further resistance? If so, how, and if not, how is their action on bacteria different than just plain soap?
Americans now seem to be getting fanatic about sterility, and people are trying to raise their children in an almost "germ-free" environment. We have a question from a woman who says that she has several friends, young mothers, generally, who seem to overuse antibacterial products. She asks: Is it not true that the presence of some "germs" in moderation is actually good for the development of our immune system?
In one of the programs in the Evolution broadcast series, there was the story of the leafcutter ants that culture Streptomyces bacteria on their bodies and seem to use those bacteria to apply antibiotics to keep their fungal farms parasite free. This has been inferred to mean that somehow the Streptomyces and the antibiotics they produce have been evolving with the enemy, and this is a kind of use that appears to have been going on for 15 million years without permanent resistance being developed. Is there anything we can do to put ourselves in that situation versus the more static situation we're in now?
Could you give an explicit description of how evolutionary theory informs integrated pest management? I think the cross-fertilization here between bacteria and antibiotic resistance and agricultural pests and insecticide resistance is very interesting, and I don't think many people make that connection.
Some physicians, who are quite impassioned, say they would like to prescribe fewer antibiotics, but their patients demand them. Since in effect they cannot be absolutely positive there isn't a bacterium involved, when, say, a parent brings in a young child who is ill, and they can't be absolutely certain that there won't be bacterial complications as a result of a viral illness, they would like to know how the public will be educated and who is going to take on the job, so that patients will basically get off the doctors' backs and let their colds run their course.
Another part of that question is that doctors are afraid of being sued if they don't prescribe an antibiotic and a bacterial infection does develop. So from the medical perspective of overuse of antibiotics, how might we address this basic problem in the interface between healthcare providers and the consuming public?
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 Panelist Bios
Tamar Barlam (a woman) Tamar Barlam is director of the Project on Antibiotic Resistance at the Center for Science in the Public Interest, in Washington, D.C. An M.D. board-certified in infectious disease, she has been involved in antibiotic policy and physician training in hospitals. She is on leave of absence from Harvard Medical School where she is an assistant professor of medicine.
George W. Beran George W. Beran is distinguished professor of preventive veterinary medicine at Iowa State University in Ames, Iowa. His research and teaching career has been in the epidemiology of antimicrobial resistance and diseases transmitted between animals and humans through foods of animal origin. He was a member of the National Research Council Committee on Drug Use in Animals.
Stuart B. Levy Stuart B. Levy, professor of medicine and of molecular biology and microbiology, is the Director of the Center for Adaptation Genetics and Drug Resistance at Tufts University School of Medicine and staff physician at the New England Medical Center. He is president of the international organization Alliance for the Prudent Use of Antibiotics and author of The Antibiotic Paradox: How Miracle Drugs Are Destroying the Miracle (1992). He is chief scientific officer of Paratek Pharmaceuticals, Inc.
Stephen R. Palumbi Stephen R. Palumbi is professor of biology at Harvard University, where he teaches evolution, marine biology, and molecular ecology, and conducts research on populations and molecular genetics of marine animals. He is the author of The Evolution Explosion (2001), about how evolution, including antibiotic resistance, is sped up by human technology.
 Moderator Bio
Joe Levine Joe Levine, science editor for the Evolution project, earned his Ph.D. at Harvard University, where he studied the physiology and evolution of color vision. With Ken Miller, he has written widely acclaimed biology textbooks for high school and college. Since 1987, he has served as advisor to the Science Unit at WGBH, working on NOVA programs and numerous special projects.
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