PBS高端访谈:全球抗生素的过度使用就像一辆慢行列车（在线收听）

JUDY WOODRUFF: Now: the enormous benefits and significant perils of the recent upsurge in the availability of antibiotics around the world. Lisa Desjardins talks to science correspondent Miles O'Brien about the latest research. It's part of our weekly science series, the Leading Edge.

LISA DESJARDINS: Antibiotic resistance contributes to the death of 700,000 people around the world each year. Experts have predicted it will eclipse the number of people affected by cancer by 2050. One of the biggest causes is the overuse of antibiotics. On Monday, a group led by researchers from the Center for Disease Dynamics, Economics and Policies released a new study looking at the global consumption of antibiotics. They found the use of antibiotics worldwide has increased 65 percent from 2000 to 2015. Miles O'Brien is here to help us understand this latest study. Miles, first of all, just remind us, how does the overuse of antibiotics lead to these resistant diseases, sometimes called superbugs?

MILES O'BRIEN: Hello, Lisa. Yes, what happens is, antibiotics kill bacteria that make us sick. That's the simple explanation. But the bacteria over time evolve and develop an ability to survive the onslaught of the antibiotics. They, in essence, get smart. So, over time, bacteria survive that have resistance built in to the antibiotic themselves. Alexander Fleming, who invented penicillin, discovered penicillin, just before World War II, warned against its over use precisely because of this. Here's a few more words about how antibiotic resistance works from Dr. Helen Boucher of the Tufts University Medical Center.

DR.HELEN BOUCHER, Tufts University Medical Center: Resistance happens naturally. So, bacteria have various mechanisms to survive. And so if they're presented with an environment that is not so good, that is, there's an antibiotic

trying to break through their cell wall, they might build a stronger cell wall, or they might -- if there's an antibiotic coming in, they might pump it out. So they figure out ways to evade the effect of the antibiotic.

MILES O'BRIEN: So this study should give us quite a bit of pause, because it means, with more antibiotics in use, there are more bugs out there that develop the resistance, so-called superbugs. And now we have a much better global picture of the scope of the problem.

LISA DESJARDINS: That seems to be what's new here, is just the scope of this study, 76 countries' worth of data over 15 years. And where did they see the biggest increases in antibiotic use? Obviously, globally, but where specifically?

MILES O'BRIEN: So, Lisa, they found the biggest contributor to this problem is in low- to mid-income countries. Back in 2000, the usage of antibiotics in the lower- to mid-income countries vs. high-income countries was about equal. In 2015, the usage in those low- to mid-income countries doubled. So, that's a significant thing. That's good news for these countries. It means that GDP has improved, income is greater. They have access to these drugs. All these things are good. But the consequences of their overuse are just magnified.

Here is Eili Klein, who is the lead author of the study.

EILI KLEIN, Center for Disease Dynamics, Economics and Policy: Unlike, in high-income countries, where, when you go to the -- the primary barrier to getting antibiotics is, you have to go to the doctor to see -- to get a prescription. In many low- and middle-income countries, the barrier is the ability to afford the drugs. And so increased economic activity allows for increased ability to purchase all sorts of things, all types of goods, including antibiotics.

MILES O'BRIEN: OK, so the good news is that, in the higher-income countries, the increase in antibiotics use is only about 6 percent. So the knowledge of this problem and the efforts to guard against it may be having some effect. But this is a real conundrum for people in medicine, Lisa, because doctors, on an individual basis, they want to make us well, and they probably have about five minutes to diagnose us anyway. And so, in the individual case, it might make more sense to give that Z-Pak to that patient. But they also need to be thinking about society at large, and that's not an easy thing to weigh when you are looking at a patient who is sick and could use those antibiotics to feel better.

LISA DESJARDINS: And I think that's my biggest question here. The study really gives me and I think many of our viewers a lot of pause, but the incentives, as you say, all go the other way, toward prescribing antibiotics right now. Does this study have any recommendations for how to lower our use of antibiotics appropriately?

MILES O'BRIEN: You know, it's interesting. The recommendations were a little bit surprising to me. One of them was, we should be more focused on getting people vaccinated. Well, on the face of it, well, wait a minute, vaccines are for viruses, not bacteria, which is what we're talking about here. But what happens is, people get sick from viruses. Doctors mistakenly give those people antibiotics, which do nothing for viruses, and that just furthers the problem. Another thing that was discussed in the paper is the idea that, as these emerging nations grow, as cities become more populated, the issue of clean water and sanitation, the sources of many diarrheal diseases, need to be focused on a lot more, because that is ultimately why people seek out antibiotics in many cases. Here's more from Eili Klein.

EILI KLEIN: If you look at the history of the high-income countries in the 20th century, the primary driver that reduced infectious diseases was improvement in infrastructure, reducing -- eliminating bacteria and other diseases from the water. And so investments in infrastructure, investments in vaccines that can prevent diseases can be a really beneficial -- can be really beneficial to low- and middle-income countries, in terms of preventing disease and then reducing the need for antibiotics.

LISA DESJARDINS: There, Eili Klein laid out the hope, the prescription. But if society doesn't actually deal with this problem, what happens in the future if we do not lower our antibiotic consumption?

MILES O'BRIEN: Well, this is something we all really need to pay attention to, Lisa. The projections are, by 2030, our use of antibiotics, if nothing changes, will be triple what it is today. And what that means is, there are going to be many more antibiotics which become really just basically useless, more so-called superbugs out there. And we are facing the prospect of a post-antibiotic world. We take for granted these miracle drugs, which really since World War II have just dramatically changed medicine in ways that it would take too long to enumerate right now. But we could get back to a world, Lisa, if nothing is done, where something as simple as a cut or a blister could kill you, which is what the world was like before we had antibiotics. So it's time -- this is like a slow-motion train wreck. Researchers have been warning us all about it. And it kind of reminds me a little bit of climate change. But it's time to get a handle on this, because, right now, more than a half-million a year people globally are dying for lack of antibiotics.

LISA DESJARDINS: Something for each of us to think very carefully about. Miles O'Brien, thank you for bringing us this story.

MILES O'BRIEN: You're welcome, Lisa.

茱蒂伍德：现在：近来世界各地的抗生素使用热潮，好处多多，然而却又危险重重。丽莎·德贾斯丁与科学记者迈尔斯·奥布赖恩展开对话，探讨了这项最新研究。这也是我们每周科学系列Leading Edge的一部分。

丽莎·德贾斯丁：抗生素耐药性每年导致全球死亡人数达700,000。专家们预测，至2050年，它将超过因癌症死亡的人数。其中最重要的一个原因就是抗生素的滥用。上周一，动态疾病、经济和政策研究中心的研究人员率领了一支研究团队，就全球抗生素消费，发布了一项最新研究成果。他们发现2015年全世界抗生素的使用量，与2000年相比，增加了65%。迈尔斯·奥布赖恩做客节目，帮助我们理解这项最新研究。迈尔斯，首先，请提醒我们，滥用抗生素如何导致了耐药性疾病的产生，有时我们也称之为“超级细菌”？

迈尔斯·奥布赖恩：你好，丽莎。是的，抗生素杀死了致病细菌。这个解释很简单。但随着时间的推移，这种细菌会进化并发展出了能够抵御抗生素的能力。从本质上说，他们变得更聪明了。因此，随着时间的推移，细菌自身能够产生耐药性，抵御抗生素。二战前，亚力山大·弗莱明发明了青霉素，但他警告说，青霉素不得过度使用，明确指出就是因为这个原因。关于抗生素的耐药性，塔夫斯大学医学中心的海伦·鲍彻博士有几句话送给我们。

海伦·鲍彻博士，塔夫斯大学医学中心：抗药是自然发生的。那么，细菌存在多种生存机制。因此，如果他们遇到了一个不太好的环境，也就是说，有一种抗生素试图突破他们的细胞壁，他们可能会建立一个更强大的细胞壁，或者他们可能——如果有抗生素进来，他们可能会把它抽出来。所以他们想出了躲避抗生素的方法。

迈尔斯·奥布赖恩：本研究应让我们停下来想一想，因为这意味着，随着抗生素越来越多的使用，会有更多的细菌发展出抗药性，也就是所谓的“超级细菌”。现在我们对这一问题的波及范围有了更全面的了解。

丽莎·德贾斯丁：这似乎正是新的地方，就是这项研究涵盖的范围，76个国家，超过15年的数据。抗生素使用量增长最多的地方是哪里？显然，在全球范围内都有增长，但具体在哪里？

迈尔斯·奥布赖恩：那么，丽莎，他们发现问题最大的就是中低收入国家。但回到2000年，中低收入国家与高收入国家的抗生素使用情况大致相同。而2015年，那些中低收入国家的使用量增加了一倍。所以，这很重要。这对这些国家来说是个好消息。这意味着国内生产总值有所改善，收入更高。他们已经可以使用这些药物。所有这些都是好的。但是他们过度使用的后果也放大了。这是伊利·克莱因，此项研究报告的主要作者。

伊利·克莱因，动态疾病、经济和政策研究中心：不同的是，在高收入国家，获得抗生素的主要障碍是，你必须去看医生才能拿到处方。而在许多中低收入国家，障碍则是药品价格的负担能力。因此，经济活动的增加使人们能够购买各种各样的东西，包括各种各样的商品，也包括抗生素。

迈尔斯·奥布赖恩：好吧，好消息是，在高收入国家，抗生素的使用量只有6%左右。因此，对这个问题的认识和防范措施可能会起到一定作用。但对医学界来说，这是一个真正的难题，丽莎，因为医生们从个人角度来讲，希望我们康复，而且他们大概只有五分钟的时间来对我们进行诊断。所以，在个案中，给病人开Z-Pak，似乎更说得通。但是他们也需要考虑整个社会，当你看到一个生病的病人，如果使用这些抗生素会感觉更好，这件事就很难权衡。

丽莎·德贾斯丁：我想这是我最大的问题。这项研究让我们停下来想一想，包括我自己，我想还包括我们的很多观众，但是，正如你所说的那样，这些激励措施都与此背道而驰，反而让医生开了抗生素。这项研究对如何适当降低抗生素的使用有什么建议吗？

迈尔斯·奥布赖恩：你知道，这很有趣。这些建议对我来说有点让人吃惊。其中之一是，我们应该将努力更多地集中在让人们接种疫苗上。好吧，从表面上看，等一下，疫苗是针对病毒的，不是针对细菌的，正是我们在这里探讨的。但是，人们会因为病毒而生病。医生误给那些人开了抗生素，而这对病毒毫无意义，这就是进一步的问题了。本文讨论的另一件事是，这些新兴国家发展了，城市人口变得越发稠密，那么干净水源和卫生问题就需要得到更多的关注，那是很多腹泻疾病的来源，因为这正是最终人们在许多情况下寻求抗生素帮助的原因。伊利·克莱因为我们带来更多内容。

伊利·克莱因：如果你看看二十世纪高收入国家的历史，改善基础设施的原动力就是减少传染病的发生，减少水中细菌及其他水源疾病。因此，投资基础设施，投资预防疾病的疫苗，可能非常有益——对低收入和中等收入国家确实有益，在预防疾病和减少抗生素需求方面。

丽莎·德贾斯丁：伊利·克莱因找到了希望，处方。但是，如果社会不真正处理这个问题，如果我们不降低抗生素消费，将来会怎样呢？

迈尔斯·奥布赖恩：嗯，这是我们大家都需要注意的事情，丽莎。我们的预测是，到2030年，如果没有改变，我们的抗生素使用量将是现在的三倍。那意味着，将有更多的抗生素，失去效用，出现更多的所谓“超级细菌”。我们全球正面临着后抗生素环境。我们认为使用这些神奇药物是理所当然的，而且自二战以来，它显著改变了我们的医药使用方式，这种例子不胜枚举。但我们可以回到一个世界，丽莎，如果什么都不做，在那里，像切破口子或起个水泡这样简单的事就会要你的命，在我们没有抗生素之前，世界就是这个样子。所以时间到了——这就像是一列慢行的火车残骸。研究人员一直在警告我们。这让我有点联想到了气候变化。但现在该处理这个问题了，因为现在全球每年有50多万人因缺乏抗生素而面临死亡。

丽莎·德贾斯丁：我们每个人都应该仔细考虑一下。迈尔斯·奥布赖恩，谢谢你做客节目。

迈尔斯·奥布赖恩：不客气，丽莎。