来自中国的超级细菌：百万亿美元级别的风险

美国国防部研究人员在上个月宣布了一项令人震惊的发现： 他们在一位到军队诊所接受治疗的宾夕法尼亚州女性体内，发现了一种耐抗生素大肠杆菌菌株。这是美国首次在人体内发现这种细菌。这种超级细菌具备粘菌素抵抗力，而粘菌素是临床使用常规方案失败后才会使用的一种抗生素。

消息一出，随即引发了激烈讨论，凸显出全世界对于这一发现结果的重视。在上周发表的文章中，科学家们警告这“将是一种具备广泛耐药性的细菌出现前的前奏。”正如美国疾病预防和控制中心主任所说：“如果我们不采取紧急行动，抗生素将走到尽头。”

好在据《华盛顿邮报》（Washington Post）报道，目前，这种超级细菌可以用其他抗生素治疗，但“研究人员担心，其抗粘菌素基因mcr-1，可能传播给已经能够躲避别的抗生素的其他细菌。”如果发生这种情况，我们可能失去任何可行的预防措施。

超级细菌已经成为严重的公共健康问题。据Vox统计，“仅在美国，每年因耐抗生素传染病导致的死亡人数达到23,000人，患病人数达200万。英国的一份报告显示，到2050年，耐抗生素传染病导致的死亡人数将超过癌症。”

此前，研究人员曾在亚洲和欧洲发现过这种超级细菌。它的出现在提醒我们，现代社会过度追求生产率将会导致意外后果。肉食品生产行业为增加产量过度使用抗生素，加快了超级细菌的出现。美国80%的抗生素被用于牲畜。北卡罗来纳州的农场动物使用的抗生素数量，超过了所有美国人所用抗生素数量的总和。

研究人员认为，此次发现的抗粘菌素大肠杆菌来自中国的禽畜养殖场。抗生素在中国被用于为猪增肥。至少一种美国农场动物也感染了这种细菌： 美国卫生及公共服务部（Department of Health and Human Services）最近在美国的猪大肠内发现了这种细菌菌株。

除了追求生产率，超级细菌的出现也揭露出另外一种更为广泛的现象： 我们对安全的关注，可能正在让我们变得越来越不安全。以富裕国家日益增加的过敏症为例。许多研究人员认为，我们为了让孩子保持清洁进而避免疾病，反而让他们的免疫系统很难在早期接触细菌，导致他们在成年以后，自身免疫系统无法发挥正常作用。在农场内长大的孩子，过敏比率远远低于经常使用杀菌香皂的孩子。

同样，过度使用抗生素治疗人类疾病，也是导致超级细菌出现的原因之一。医生诊所和医院开出的抗生素中，有三分之一是没有必要的。但医生往往会根据患者或家长的要求开具抗生素处方。

为了应对超级细菌日益严峻的威胁，政界和医疗界一致认为，我们必须控制农业和医疗行业滥用抗生素的情况，并应鼓励新药开发。这样一来会有许多行业受到影响。

有一个行业将会迎来机遇——农业。2014 - 2015年，无抗生素肉类的销量上涨了20%。提高消费者对超级细菌威胁的认识，必将加快这一趋势，从餐厅和食品杂货店到农场和牧场的整个食物价值链都将受到影响。

除了消费者带来的压力外，监管也有助于推动向无抗生素肉类的转变。去年10月份，加州通过了一项严格的法律，限制农业对抗生素的使用。不能适应消费者偏好转变和限制规定的农场将受到惩罚。

超级细菌威胁也有可能改变药物开发领域的经济状况。目前，在制药行业，新抗生素开发并不是特别有利可图的领域。结果导致目前进行临床开发的抗生素仅有37种，而癌症药物或疫苗却有800多种。提高对新抗生素需求的认识，可以改变这种状况。1月份，由大型制药公司组成的联盟，呼吁各国政府在新抗生素开发领域提供激励。

新抗生素的经济模式绝对不能基于数量，否则可能刺激制药公司，加剧我们当前面临的医生开药过量的问题。相反，为成功药物开发提供数十亿美元的一次性奖励，可以刺激对抗生素研发的投资，避免激励错位的情况。事实上，各国政府已经在考虑这些措施。

超级细菌的出现必将影响到不同的行业，如食品服务业、医学和农业等。一项估算显示，如果找不到解决方案，耐抗生素细菌给全球经济造成的累计损失有可能达到100万亿美元。

包括经济学家吉姆•奥尼尔在内的许多人都认为，超级细菌问题与气候变化问题同样重要。超级细菌问题带来的高风险，足以促使各国和国际社会以前所未有的规模行动起来。否则，我们可能重新过上20世纪抗生素改变世界之前的生活——“肮脏，野蛮，寿命缩短”。或者就像英国首相戴维•卡梅伦最近在G7大会上所说的那样，“正如我们所知的现代医学的末日。” （财富中文网）

译者：刘进龙/汪皓

Department of Defense researchers announced a shocking finding last month: they had identified an ominous, antibiotic-resistant strain of E. Coli in a Pennsylvania woman seeking medical treatment at a military clinic. This is the first time this bacteria has been positively identified in a human in America. The superbug is resistant to colistin, an antibiotic used only when alternatives have failed.

The announcement has prompted a host of statements highlighting the global significance of this finding. In an article published last week, scientists warned this “heralds the emergence of a truly pan-drug resistant bacteria.” As the director of the Centers for Disease Control and Prevention (CDC) put it, “It is the end of the road for antibiotics unless we act urgently.”

While the current superbug is thankfully treatable with other kinds of antibiotics, according to the Washington Post, “researchers worry that its colistin-resistance gene, known as mcr-1, could spread to other bacteria that can already evade other antibiotics.” In that case, we could be out of viable defenses.

Superbugs are already an enormous public health problem. According to Vox, “In the United States alone, antibiotic-resistant infections are now associated with 23,000 deaths and 2 million illnesses every year. By 2050, a report out of the UK suggested drug-resistant infections will kill more people than cancer.”

The current superbug, which researchers had previously seen in Asia and Europe, is a reminder of the unintended consequences of the modern quest for productivity. Aggressive use of antibiotics in the meat production industry to maximize yield has acceleratedthe development of superbugs. 80% of antibiotics in the US are used on livestock. North Carolina farm animals receive more of these drugs than all Americans combined.

Researchers believe that the colistin-resistant E. Coli originated in Chinese livestock farms, where the antibiotic is used to help fatten pigs. It has also infected at least one American farm animal: the Department of Health and Human Services recentlyspotted the same strain in a pig intestine in the US.

In addition to our quest for productivity, the development of superbugs also reveals another broader phenomenon: our widespread zeal for safety may be making us less safe. Take the rise of allergies in rich countries, for example. Many researchers believe that in scrambling to keep our children clean—and thus safe from disease—we have prevented their immune systems from gaining early exposure to germs, causing them to malfunction later in life. Kids who grow up on farms have lower rates of allergies, while those more often exposed to antibacterial soap have higher rates.

Likewise, over-prescription of antibiotics to treat human conditions is also contributing to the development of superbugs. Roughly a third of all antibiotics prescribed in doctors’ offices and hospitals are unnecessary—often the result of demanding patients or parents.

To counteract the increasing threat of superbugs, politicians and doctors agree, we must restrain abuse in both agriculture and medicine and also stimulate new drug development. Doing so will impact a number of sectors.

An obvious area of opportunity is in agriculture. Sales of antibiotic-free meats jumped 20% in 2014-2015. Heightened consumer awareness of the superbug threat will only accelerate this trend, affecting the entire food value chain from restaurants and grocery stores to farmers and ranchers.

In addition to consumer pressure, regulations will also drive a shift to antibiotic-free meats. Last October, California passed a strict law limiting the use of antibiotics in agriculture. Farms that can’t adapt to these shifting consumer preferences and restrictive regulations will suffer.

The superbug threat might also change the economics of drug development. Today, creating new antibiotics is not particularly lucrative for the pharmaceutical industry. As a result, there are only 37 antibiotics in clinical development, compared with over 800 cancer drugs or vaccines. Increased awareness of the need for new antibiotics could change this. In January, a coalition of major drug companies called for governments to offer incentives in this space.

The economic model for new antibiotics must not be based on volume, since that would incentivize drug companies to encourage the same over-prescription problem we face today. Instead, lump-sum prizes for successful drug development, valued in the billions of dollars, could spur investment in antibiotic research and development without the misaligned incentives. And indeed, governments have been considering just these measures.

The development of superbugs will certainly ripple through disparate industries, from food service to medicine and agriculture. Barring a solution, one estimate tallies the cumulative hit to the global economy from antibiotic-resistant bacteria could be as high as $100 trillion.

Some, including economist Jim O’Neill, suggest the problem is as significant as climate change. The stakes are high enough that the problem could drive national and international mobilization on an unprecedented scale. If not, we could experience life as it was before antibiotics revolutionized the world in the 20th century—“nasty, brutish, and short(er).” Or, as British Prime Minister David Cameron recently said at a G7 meeting, “the end of modern medicine as we know it.”