新闻周刊:对抗耐药菌(4)（在线收听）

Medical researchers are now searching for other approaches. One involves recruiting biologists with a flair for evolutionary theory into the war on bugs. In the 1990s, Riley started out at Harvard and Yale studying the ways viruses kill bacteria and bacteria kill one another. In 2000, a colleague casually asked her if the work had any application to human health. “I had never thought about that,” she says. “But suddenly everything clicked for me, and I became consumed by that question.”

医学研究人员正在寻找其他方法。其中一项是招募具有进化论天赋的生物学家加入到对细菌的战争中来。20世纪90年代，赖利开始在哈佛和耶鲁大学研究病毒杀死细菌和细菌相互杀死的方式。2000年，一位同事偶然问她，这项工作是否适用于人类健康。“我从来没有想过这个，”她说。“但突然间，我的一切都豁然开朗，我被这个问题吸引住了。”

Riley has since spent the past two decades looking into applying the warfare strategy of viruses to the problem of resistant infections in humans. Viruses called “phages,” which are basically chunks of genetic material wrapped in a protective protein, will pierce the cell wall of a bacterium and hijack its genetic machinery, turning the bacterium into a factory for making more viruses. Riley also studies how bacteria sometimes also kill other bacteria in the competition for food. A colony of bacteria will sometimes elbow out a competitor by producing poisonous proteins called “bacteriocins.”

莱利在过去20年里一直在研究将病毒的作战策略应用于人类的耐药感染问题。被称为“噬菌体”的病毒，基本上是包裹在保护性蛋白质中的大块遗传物质，它将穿透细菌的细胞壁，劫持其遗传机制，把细菌变成制造更多病毒的工厂。莱利还研究了细菌有时是如何在争夺食物的过程中杀死其他细菌的。一群细菌有时会通过产生一种叫做“细菌素”的有毒蛋白质来对付其他细菌。

Riley's goal isn't just to kill dangerous bacteria—it's also to protect the beneficial ones. Of the roughly 400 trillion bacteria living in or on each of our bodies, the vast majority are helpful or benign—only one 10-thousandth of a percent of them are potentially harmful, she says. Commonly prescribed “broad spectrum” antibiotics like penicillin, ciprofloxacin and tetracycline don't discriminate between good and bad bacteria—they wipe out them all. That not only helps lead to the emergence of resistant bacteria but also causes problems for patients.

莱利的目标不仅仅是杀死危险的细菌，也是保护有益的细菌。她说，生活在我们每个人体内或体内的大约400万亿细菌中，绝大多数是有益或有益的，只有千分之一的细菌是潜在有害的。常用的广谱抗生素如青霉素、环丙沙星和四环素不能区分好细菌和坏细菌——它们会将细菌全部消灭。这不仅有助于导致耐药细菌的出现，还会给病人带来问题。

“An antibiotic is like throwing an H-bomb at an infection,” Riley says. “You kill 50 percent or more of all the bacteria in the body, and a lack of healthy bacteria has been linked to obesity, depression, allergies and other problems.” Phages and bacteriocins, on the other hand, can in theory be tuned to take out a colony of infection-causing bacteria in a patient, all without harming the normal flora or creating a fertile breeding ground for resistant bugs.

“抗生素就像在感染上扔氢弹，”莱利说。“你杀死了身体中50%或更多的细菌，缺乏健康的细菌与肥胖、抑郁、过敏和其他问题有关。”另一方面，从理论上讲，噬菌体和细菌素可以在不损害正常菌群或为耐药细菌创造肥沃繁殖地的前提下，清除病人体内的一群引起感染的细菌。