來自中國的超級細菌:百萬億美元級別的風險
美國國防部研究人員在上個月宣布了一項令人震驚的發現: 他們在一位到軍隊診所接受治療的賓夕法尼亞州女性體內,發現了一種耐抗生素大腸桿菌菌株。這是美國首次在人體內發現這種細菌。這種超級細菌具備粘菌素抵抗力,而粘菌素是臨床使用常規方案失敗后才會使用的一種抗生素。 消息一出,隨即引發了激烈討論,凸顯出全世界對于這一發現結果的重視。在上周發表的文章中,科學家們警告這“將是一種具備廣泛耐藥性的細菌出現前的前奏。”正如美國疾病預防和控制中心主任所說:“如果我們不采取緊急行動,抗生素將走到盡頭。” 好在據《華盛頓郵報》(Washington Post)報道,目前,這種超級細菌可以用其他抗生素治療,但“研究人員擔心,其抗粘菌素基因mcr-1,可能傳播給已經能夠躲避別的抗生素的其他細菌。”如果發生這種情況,我們可能失去任何可行的預防措施。 超級細菌已經成為嚴重的公共健康問題。據Vox統計,“僅在美國,每年因耐抗生素傳染病導致的死亡人數達到23,000人,患病人數達200萬。英國的一份報告顯示,到2050年,耐抗生素傳染病導致的死亡人數將超過癌癥。” 此前,研究人員曾在亞洲和歐洲發現過這種超級細菌。它的出現在提醒我們,現代社會過度追求生產率將會導致意外后果。肉食品生產行業為增加產量過度使用抗生素,加快了超級細菌的出現。美國80%的抗生素被用于牲畜。北卡羅來納州的農場動物使用的抗生素數量,超過了所有美國人所用抗生素數量的總和。 研究人員認為,此次發現的抗粘菌素大腸桿菌來自中國的禽畜養殖場。抗生素在中國被用于為豬增肥。至少一種美國農場動物也感染了這種細菌: 美國衛生及公共服務部(Department of Health and Human Services)最近在美國的豬大腸內發現了這種細菌菌株。 除了追求生產率,超級細菌的出現也揭露出另外一種更為廣泛的現象: 我們對安全的關注,可能正在讓我們變得越來越不安全。以富裕國家日益增加的過敏癥為例。許多研究人員認為,我們為了讓孩子保持清潔進而避免疾病,反而讓他們的免疫系統很難在早期接觸細菌,導致他們在成年以后,自身免疫系統無法發揮正常作用。在農場內長大的孩子,過敏比率遠遠低于經常使用殺菌香皂的孩子。 同樣,過度使用抗生素治療人類疾病,也是導致超級細菌出現的原因之一。醫生診所和醫院開出的抗生素中,有三分之一是沒有必要的。但醫生往往會根據患者或家長的要求開具抗生素處方。 為了應對超級細菌日益嚴峻的威脅,政界和醫療界一致認為,我們必須控制農業和醫療行業濫用抗生素的情況,并應鼓勵新藥開發。這樣一來會有許多行業受到影響。 有一個行業將會迎來機遇——農業。2014 - 2015年,無抗生素肉類的銷量上漲了20%。提高消費者對超級細菌威脅的認識,必將加快這一趨勢,從餐廳和食品雜貨店到農場和牧場的整個食物價值鏈都將受到影響。 除了消費者帶來的壓力外,監管也有助于推動向無抗生素肉類的轉變。去年10月份,加州通過了一項嚴格的法律,限制農業對抗生素的使用。不能適應消費者偏好轉變和限制規定的農場將受到懲罰。 超級細菌威脅也有可能改變藥物開發領域的經濟狀況。目前,在制藥行業,新抗生素開發并不是特別有利可圖的領域。結果導致目前進行臨床開發的抗生素僅有37種,而癌癥藥物或疫苗卻有800多種。提高對新抗生素需求的認識,可以改變這種狀況。1月份,由大型制藥公司組成的聯盟,呼吁各國政府在新抗生素開發領域提供激勵。 新抗生素的經濟模式絕對不能基于數量,否則可能刺激制藥公司,加劇我們當前面臨的醫生開藥過量的問題。相反,為成功藥物開發提供數十億美元的一次性獎勵,可以刺激對抗生素研發的投資,避免激勵錯位的情況。事實上,各國政府已經在考慮這些措施。 超級細菌的出現必將影響到不同的行業,如食品服務業、醫學和農業等。一項估算顯示,如果找不到解決方案,耐抗生素細菌給全球經濟造成的累計損失有可能達到100萬億美元。 包括經濟學家吉姆?奧尼爾在內的許多人都認為,超級細菌問題與氣候變化問題同樣重要。超級細菌問題帶來的高風險,足以促使各國和國際社會以前所未有的規模行動起來。否則,我們可能重新過上20世紀抗生素改變世界之前的生活——“骯臟,野蠻,壽命縮短”。或者就像英國首相戴維?卡梅倫最近在G7大會上所說的那樣,“正如我們所知的現代醫學的末日。” (財富中文網) 譯者:劉進龍/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.” |