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未来的抗生素

更新时间:2014-1-2 14:03:53 来源:华尔街日报中文网 作者:佚名

Antibiotics Of The Future
未来的抗生素

Scientists are working to develop new strategies to combat the growing threat of germs that current antibiotics can't fight.

科学家正在努力发掘新的对策,以期对抗目前的抗生素无法战胜的那些病菌日益增大的威胁。

Some researchers are testing new substances, such as silver, to combine with antibiotics to boost their killing power. Other researchers are making use of genetic sequencing of bacteria to help develop killer drugs at a faster pace than medical science was capable of in the past.

一些研究人员在试验用银等物质与抗生素结合来提高它们的杀伤力,其他研究人员则在利用细菌基因排序,以帮助研发比以前的医学手段更快杀灭细菌的新药。

Another strategy aims to render harmful bacteria incapable of infecting people, rather than killing the germs outright. One such technique would neutralize disease-causing toxins by disrupting the bacteria's internal mechanisms.

另一种策略意在让 有害细菌无法感染人类而不是将病菌 一举消灭。这样一种技术可以通过破坏细菌的内在机理来中和致病毒素。

Antibiotic resistance is a growing threat to public health, medical officials say. Common germs such as Escherichia coli, or E. coli, which can cause urinary tract and other infections, and Neisseria gonorrhoeae, which causes gonorrhea, are becoming harder to treat because they increasingly don't respond to antibiotics. Some two million people in the U.S. are infected each year by antibiotic-resistant bacteria and 23,000 die as a result, according to the Centers for Disease Control and Prevention. The CDC says it doesn't have historical numbers.

医疗官员说,抗生素耐药性对公共卫生构成了越来越大的威胁。像能够引起尿路及其它感染的大肠杆菌和引起淋病的淋球菌这些常见病菌都变得越发难以治疗,因为它们对抗生素的反应日渐减弱。根据美国疾病控制与预防中心(Centers for Disease Control and Prevention,简称疾控中心)的数据,美国每年有大约两百万人感染抗药性细菌,由此造成的死亡人数达23,000人。疾控中心说它没有历史数据。

One of the biggest threats is from Enterobacteriaceae, a family of germs that naturally lives in the gut and includes E. coli, the CDC says. There are about 9,000 cases a year of infections from the germs that can't be treated with usual antibiotics, resulting in 610 deaths. In 1998, there was just one case. Patients who don't respond to normal antibiotics are given older drugs that had been discontinued because of severe side effects, such as kidney damage, the CDC says.

该中心说,最大的威胁之一是肠杆菌,这是一个自然栖居于肠道的病菌族群,其中包括大肠杆菌。现在每年有大约9,000例病例感染这种普通抗生素无法治愈的病菌,导致死亡的人数为610人,而1998年却只有一例。疾控中心说,医生现在给对 普通抗生素没有反应的人开的都是老药,那些药过去因引起肾功能损害等严重副作用而被停用了。

Scientists say that Enterobacteriaceae are particularly hard to kill because of an outer cell wall that prevents many antibiotics from penetrating. James J. Collins, a professor of biomedical engineering at Boston University and Harvard University, and his colleagues recently discovered that adding trace amounts of silver -- long known to have antimicrobial properties -- allows the common antibiotic vancomycin to work against E. coli, whereas the antibiotic isn't effective against the microbe on its own. The silver appears to make the outer walls of the bacteria more permeable, allowing the antibiotic to get in and do its job, says Dr. Collins, who published the findings in the journal Science Translational Medicine in June.

科学家说肠杆菌特别难消灭,因为它的一个外层细胞壁可以阻止很多抗生素的侵入。身为波士顿大学和哈佛大学生物医学工程教授的詹姆斯·J·科林斯(James J. Collins)最近和他的同事发现加入微量的银——人们早已知道它具有抗菌的特性——可以让万古霉素这样的普通抗生素杀灭大肠杆菌,而这种抗生素仅靠自身是不能有效消灭那种细菌的。科林斯说,看来银让细菌的外层细胞壁更容易被穿透,使抗生素得以进入并发挥它的作用。他在六月的《科学转化医学》(Science Translational Medicine)杂志上发表了这项研究成果。

Some pharmaceutical companies are experimenting with other types of additives with the aim of short-circuiting bacteria's defenses.

一些制药公司也在试验其它类型的添加剂,旨在破坏细菌的防御体系。

Researchers at Merck & Co., in Whitehouse Station, N.J., are targeting an enzyme called beta-lactamase that lives in certain bacteria and neutralizes antibiotics sent to destroy them. By adding an enzyme-inhibiting agent called MK-7655 to the antibiotic imipenem, researchers managed to kill about 97% of a type of antibiotic-resistant bacteria that causes urinary-tract infections and pneumonia, according to Nicholas Kartsonis, head of clinical development of antibacterial, antifungals and non-hepatology viruses at Merck Research Labs.

美国新泽西州怀特豪斯站(Whitehouse Station, N.J.)的默克公司(Merck & Co.)研究人员现在把目标锁定在一种名为β-内胺的上面,这种?栖身于某些细菌中并让奉命去摧毁它们的抗生素失去效力。按照默克研究实验室(Merck Research Labs)抗菌素、抗真菌剂和非肝胆疾病病毒临床开发负责人尼古拉斯·卡特索尼斯(Nicholas Kartsonis)的说法,通过在抗生素亚胺培南中加入一种名为MK-7655的抑制剂,研究人员成功地将一种引起尿路感染和肺炎的抗药性细菌杀灭了97%。

Synthetic Biologics Inc. is taking advantage of beta-lactamase's ability to neutralize antibiotics by adding a modified version of the enzyme to the drugs. The aim is to prompt the antibiotic to break down when it reaches the bowel, where side effects and drug resistance for bacteria called Clostridium difficile, or C. difficile, develops, but to leave the antibiotic intact in the bloodstream. The process should allow larger doses of antibiotics to be administered without the patient suffering typical side effects such as gastrointestinal problems, says John Monahan, who heads research and development for the Rockville, Md.-based company.

合成生物制剂公司(Synthetic Biologics Inc.)通过在药物里添加一种经过改良的β-内胺来发挥这种?中和抗生素的能力,其目的是在抗生素到达肠道(一种名为艰难梭状芽孢杆菌(Clostridium difficile, or C. difficile)的细菌会在此产生副作用和抗药性)时促进抗生素的分解,但却会让血液中的抗生素毫发无损。总部位于马里兰州罗克维尔(Rockville, Md.)的这家公司负责研究与开发的约翰·莫纳汉(John Monahan)说,这种方法将使病人能够服用更大剂量的抗生素而不会引起胃肠性问题等典型副作用。

C. difficile, which causes life-threatening diarrhea and is blamed for 14,000 deaths a year, can spread rapidly in hospital patients on antibiotics. Although there are drugs to treat C. difficile, the bacteria are resistant to many antibiotics used to treat other types of infections.

艰难梭状芽孢杆菌会引起危及生命的腹泻,每年造成了14,000人死亡。这种细菌可以在服用抗生素的住院患者中迅速传播。虽然有治疗艰难梭菌的药物,但是这种细菌对用于治疗其它类型感染的很多抗生素都具有抗药性。

Antibiotics naturally lose their effectiveness over time as bacteria populations build up resistance, and new drugs need to be continually developed to take their place. But antibiotic development by pharmaceutical companies slowed sharply after about 1990, in part because they are less profitable than other drugs used to treat chronic diseases. Compounding the problem has been an overuse of antibiotics in people and farm animals, which has accelerated the creation of antibiotic-resistant germs.

由于细菌种群抗药性的增强,抗生素会随时间自然而然地失去它们的效力,因而需要持续研发新药来取而代之。然而制药公司研发抗生素的进程在1990年前后大幅放缓,部分原因是它们的利润相比其它用于治疗慢性疾病的药而言更低。人和家畜过度使用抗生素更是加剧了这个问题,它加快了耐药细菌的生成速度。

'Antibiotics have a finite lifetime because resistance is inevitable,' says Michael Fischbach, a bioengineering and therapeutic sciences professor at the University of California, San Francisco. 'Therefore, there's always a need to innovate.'

“抗生素的寿命是有限的,因为抗性的产生不可避免,”旧金山加利福尼亚大学(University of California)的生物工程及治疗科学教授迈克尔·菲施巴赫(Michael Fischbach)说,“因此,永远都会有推陈出新的需要。”

Bacteria have ways of defending themselves against other bacteria, and most antibiotics are derived from the toxins they use. Identifying and developing new antibiotics is a long and slow process. Now, scientists are able to more efficiently scrutinize microbes for undiscovered antibiotics by sequencing their genomes and then using computer analysis to look for gene patterns that suggest a new antibiotic recipe. Typically, antibiotics are encoded by anywhere from 10 to 40 genes.

细菌有办法保护自己,使其免受其它细菌的攻击,而大多数抗生素都源自于它们所利用的毒素。发现和研发新的抗生素是一个漫长又缓慢的过程。现在科学家能够更有效地细致观察微生物,以期找到尚未发现的抗生素。他们通过给基因组测序,然后利用电脑分析结果来寻找能够提示新抗生素配方的基因模式。一般来讲,抗生素用10-40个基因进行编码。

Sean Brady, head of the Laboratory of Genetically Encoded Small Molecules at Rockefeller University in New York, and his colleagues recently zeroed in on half a dozen gene sequences. The team found that the genes were encoded for toxins that appeared in lab testing to be active against pathogens resistant to the antibiotic vancomycin, which is commonly used to treat infections in the gut. The research was published in the Proceedings of the National Academy of Science in June.

纽约洛克菲勒大学(Rockefeller University) 小分子基因编码实验室(the Laboratory of Genetically Encoded Small Molecules)负责人肖恩·布雷迪(Sean Brady)和他的同事最近瞄准了六个基因序列。该团队发现,在实验室试验中似乎可以积极抑制耐万古霉素(普遍用于治疗肠道感染的抗生素)病原体的毒素基因已经完成了编码。这项研究发表在六月的《美国国家科学院院刊》(the Proceedings of the National Academy of Science)上。

Whether the antibiotic will be useful in treating people remains to be seen, says Dr. Brady. The main problem with identifying new antibiotics isn't that they don't work, but that they cause severe side effects or toxicity, drug makers say.

这种抗生素是否在给人治病时有用还有待观察,布雷迪说。制药商说,找到新抗生素方面的主要问题不是它们不起作用,而是它们会引起严重的副作用或毒性反应。

Another group of researchers, headed by Dr. Fischbach at the University of California, has found a handful of new antibiotics that kill methicillin-resistant Staphylococcus aureus, or MRSA, by sequencing genomes of bacteria found in the environment. MRSA can cause a range of illnesses from skin infections to pneumonia and bloodstream infections.

加利福尼亚大学菲施巴赫领头的另一组研究人员对环境中发现的细菌进行基因组测序后,发现了一些能够杀灭耐甲氧西林金黄色葡萄球菌(MRSA)的新抗生素。MRSA可以引起从皮肤感染到肺炎以及血液感染的一系列疾病。

An unusual strategy doesn't aim to kill bacteria at all, but rather to make them less harmful. Since bacteria only cause infections when their population has reached a certain threshold, called a quorum, researchers are looking for ways to disrupt the chemical signals the bugs use to communicate with each other. Another approach aims to neutralize toxins or disrupt other signaling molecules that are necessary for bacteria to be infectious.

一种不同寻常的策略是根本不打算消灭细菌,而只是让细菌的有害程度降低。由于细菌只是在数量上达到一定值时(称为最低数量(quorum))才会引起感染,研究人员正在寻找途径破坏病菌之间用于互相交流的化学信号。另一种办法意图要中和毒素或者破坏细菌感染所必需的其它信号分子。

'We don't challenge them to a duel but basically confuse them into not causing infection,' says Gerry Wright, a professor of biochemistry and biomedical sciences at McMaster University in Hamilton, Ontario.

“我们并不挑起和它们的决斗,而主要是引起它们的混乱,使其不会引起感染,”加拿大安大略省哈密尔顿市(Hamilton, Ontario)麦克马斯特大学(McMaster University)的生物化学及生物医学教授格里·赖特(Gerry Wright)说。

Dr. Brady and his team at Rockefeller University demonstrated that disrupting a cluster of genes reduced the virulence of a microbe that causes infection affecting the lungs, bones and joints. The researchers published the work late last year in the Journal of the American Chemical Society.

洛克菲勒大学的布雷迪和他的团队证明,对一组基因加以干扰降低了一种能够引起肺部、骨骼和关节感染的细菌的毒性。这队研究人员去年年底将他们的研究发表在《美国化学学会会志》(Journal of the American Chemical Society)上。

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