将抗生素耐药性传播给其他微生物的罪魁祸首

科学家发现了将抗生素耐药性传播给其他微生物的罪魁祸首

Antibiotic resistance is spreading fast all over the world. When infectious bacteria mutate in a certain way and then multiply, they can become resistant to even the most powerful drugs.

抗生素耐药性正在世界各地迅速蔓延。当感染性细菌以某种方式变异然后繁殖时，它们甚至会对最强大的药物产生抗药性。

But research has revealed a worrying alternative way that antibiotic resistance can spread: an organism that passes on its resistance on to other living bacteria.

但研究揭示了另一种令人担忧的抗生素耐药性传播方式:一种将耐药性传递给其他活细菌的有机体。

In June 2012, a 35-year old man from São Paulo found himself in hospital with a myriad of problems. Alongside a diagnosis of skin cancer, he was told he harboured a potentially lethal bacterial infection. The doctors placed him on a course of chemotherapy and antibiotics, and the bacteria-killing treatment appeared to do its work. But within a month the microbe-driven fever had returned.

2012年6月，一名来自圣保罗的35岁男子因各种问题住进了医院。在被诊断出皮肤癌的同时，他还被告知患有一种可能致命的细菌感染。医生对他进行了化疗和抗生素治疗，这种杀菌疗法似乎起了作用。但不到一个月，由微生物引起的发烧又卷土重来。

The patient had contracted the well-known superbug MRSA (methicillin-resistant Staphylococcus aureus). So the medical team turned to one of the "last line of defence" antibiotics, the powerful compound vancomycin. This strain of MRSA originally had no natural defence against vancomycin, but by August that year it had become resistant, rendering the treatment ineffective.

病人感染了著名的超级细菌MRSA(耐甲氧西林金黄色葡萄球菌)。因此，医疗小组转而使用“最后一道防线”抗生素——万古霉素。这种耐甲氧西林金黄色葡萄球菌最初对万古霉素没有天然的防御，但到那年8月，它已经产生了抗药性，使得治疗无效。

Scientists would later uncover that rather than acquiring resistance through a simple mutation, the MRSA had instead been gifted a huge chunk of new DNA. Within this string of donated genetic code were the instructions for proteins that would keep the bacteria safe from the destructive work of the antibiotic.

科学家后来发现，MRSA并不是通过简单的突变获得抗性，而是被赋予了一大块新的DNA。在这一串捐赠的遗传密码中，含有蛋白质的指令，可以保护细菌免受抗生素的破坏。

But where had this DNA come from?

但这个DNA是从哪里来的?

Enter Enterococcus faecalis. This bug is typically described as a commensal bacterium (one of our "good bacteria"), which lives happily in our guts causing no harm. Our digestive tracts are a hive of microbial activity, hosting single-celled organisms in their trillions. The so-named microbiome is incredibly important for maintaining a healthy human gut, but also helps to suppress the sinister side of bugs like faecalis.

粪肠球菌。这种细菌通常被描述为共生细菌(我们的“好细菌”之一)，它快乐地生活在我们的肠子里，不会造成伤害。我们的消化道是一个微生物活动的蜂巢，容纳着数以万亿计的单细胞生物。这种所谓的微生物群对维持人体肠道健康极其重要，但也有助于抑制粪便等病菌的邪恶一面。

When patients with weakened immune systems undergo antibiotic treatments, this undesirable side can flourish. When we are given antibiotics, they indiscriminately sweep away all bacteria that have no natural defences, sometimes clearing the gut microbiome of many of its friendly inhabitants.

当免疫系统受损的患者接受抗生素治疗时，这种不良反应可能会加剧。当我们被给予抗生素时，它们会不分青红皂白地清除所有没有天然防御能力的细菌，有时还会清除肠道菌群。

But faecalis is intrinsically equipped with an arsenal of natural resistance mechanisms within its DNA, often allowing it to survive.

但粪肠球菌DNA中天生就具有一种天然的抗药机制，往往能让它存活下来。

With no oppressive neighbours around or an able immune system to keep them in check, faecalis and its resistant peers proliferate and thrive, dividing happily to move into the newly available real estate of the gut. And before long they come into close contact with their resistant and potentially disease-causing neighbours.

周围没有压迫性的邻居，也没有一个有能力的免疫系统来控制它们，粪肠球菌和它的同类抵抗者繁殖并茁壮成长，快乐地分裂，进入肠道的新领地。不久之后，它们就会与具有耐药性并可能致病的邻居密切接触。

When humans come together we often exchange ideas through language. But when bacteria come together they can exchange information through DNA-encoded instructions. This is known as horizontal gene transfer, where copies of DNA move from one cell to another.

当人们聚在一起时，我们经常通过语言交流思想。但是当细菌聚集在一起时，它们可以通过dna编码的指令来交换信息。这被称为水平基因转移，即DNA拷贝从一个细胞转移到另一个细胞。

Unfortunately, E. faecalis and its superbug compatriots have all the best information to share, information that allows them to survive antibiotics.

不幸的是，粪肠球菌和它的超级细菌同胞们有所有最好的信息可以分享，这些信息使它们能够在抗生素下存活。

Antibiotics perform a critical role in modern medicine. They're used routinely to treat infectious disease, administered pre-emptively after surgery, and have contributed to raising the average life expectancy by an average of 20 years across the globe.

抗生素在现代医学中起着至关重要的作用。通常应用于治疗传染病，在手术后被预先使用，并使全球平均预期寿命提高了20年。

This makes tackling antibiotic resistance one of the most pressing issues faced by our species today. Yet, in bacteria such as faecalis, scientists have discovered microbes colluding to escalate the danger presented by evolved antibiotic resistance.

这使得应对抗生素耐药性成为当今人类面临的最紧迫问题之一。然而，科学家们在粪便菌等细菌中发现了一些微生物，它们相互勾结，加剧了进化出的抗生素耐药性所带来的危险。

This makes understanding E. faecalis of paramount importance. Yet much of the microbe's natural, intrinsic resistance remains shrouded in mystery.

这使得了解粪肠球菌变得至关重要。然而，这种微生物的许多自然的、内在的抵抗力仍然笼罩在神秘之中。