將抗生素耐藥性傳播給其他微生物的罪魁禍?zhǔn)?/h1>

所屬教程:科學(xué)前沿

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2019年10月08日

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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.

抗生素耐藥性正在世界各地迅速蔓延。當(dāng)感染性細(xì)菌以某種方式變異然后繁殖時，它們甚至?xí)ψ顝姶蟮乃幬锂a(chǎn)生抗藥性。

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.

但研究揭示了另一種令人擔(dān)憂的抗生素耐藥性傳播方式:一種將耐藥性傳遞給其他活細(xì)菌的有機體。

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，一名來自圣保羅的35歲男子因各種問題住進了醫(yī)院。在被診斷出皮膚癌的同時，他還被告知患有一種可能致命的細(xì)菌感染。醫(yī)生對他進行了化療和抗生素治療，這種殺菌療法似乎起了作用。但不到一個月，由微生物引起的發(fā)燒又卷土重來。

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級細(xì)菌MRSA(耐甲氧西林金黃色葡萄球菌)。因此，醫(yī)療小組轉(zhuǎn)而使用“最后一道防線”抗生素——萬古霉素。這種耐甲氧西林金黃色葡萄球菌最初對萬古霉素沒有天然的防御，但到那年8月，它已經(jīng)產(chǎn)生了抗藥性，使得治療無效。

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.

科學(xué)家后來發(fā)現(xiàn)，MRSA并不是通過簡單的突變獲得抗性，而是被賦予了一大塊新的DNA。在這一串捐贈的遺傳密碼中，含有蛋白質(zhì)的指令，可以保護細(xì)菌免受抗生素的破壞。

But where had this DNA come from?

但這個DNA是從哪里來的?

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.

糞腸球菌。這種細(xì)菌通常被描述為共生細(xì)菌(我們的“好細(xì)菌”之一)，它快樂地生活在我們的腸子里，不會造成傷害。我們的消化道是一個微生物活動的蜂巢，容納著數(shù)以萬億計的單細(xì)胞生物。這種所謂的微生物群對維持人體腸道健康極其重要，但也有助于抑制糞便等病菌的邪惡一面。

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.

當(dāng)免疫系統(tǒng)受損的患者接受抗生素治療時，這種不良反應(yīng)可能會加劇。當(dāng)我們被給予抗生素時，它們會不分青紅皂白地清除所有沒有天然防御能力的細(xì)菌，有時還會清除腸道菌群。

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

但糞腸球菌DNA中天生就具有一種天然的抗藥機制，往往能讓它存活下來。

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.

周圍沒有壓迫性的鄰居，也沒有一個有能力的免疫系統(tǒng)來控制它們，糞腸球菌和它的同類抵抗者繁殖并茁壯成長，快樂地分裂，進入腸道的新領(lǐng)地。不久之后，它們就會與具有耐藥性并可能致病的鄰居密切接觸。

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.

當(dāng)人們聚在一起時，我們經(jīng)常通過語言交流思想。但是當(dāng)細(xì)菌聚集在一起時，它們可以通過dna編碼的指令來交換信息。這被稱為水平基因轉(zhuǎn)移，即DNA拷貝從一個細(xì)胞轉(zhuǎn)移到另一個細(xì)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，糞腸球菌和它的超級細(xì)菌同胞們有所有最好的信息可以分享，這些信息使它們能夠在抗生素下存活。

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.

抗生素在現(xiàn)代醫(yī)學(xué)中起著至關(guān)重要的作用。通常應(yīng)用于治療傳染病，在手術(shù)后被預(yù)先使用，并使全球平均預(yù)期壽命提高了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.

這使得應(yīng)對抗生素耐藥性成為當(dāng)今人類面臨的最緊迫問題之一。然而，科學(xué)家們在糞便菌等細(xì)菌中發(fā)現(xiàn)了一些微生物，它們相互勾結(jié)，加劇了進化出的抗生素耐藥性所帶來的危險。

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

這使得了解糞腸球菌變得至關(guān)重要。然而，這種微生物的許多自然的、內(nèi)在的抵抗力仍然籠罩在神秘之中。