科学美国人60秒 刺猬宿主抗生素耐药性的进化（在线收听）

Hedgehogs Host the Evolution of Antibiotic Resistance

刺猬宿主抗生素耐药性的进化

Karen Hopkin: This is Scientific American’s 60-Second Science. I’m Karen Hopkin.

Hedgehogs are a lot of things. They’re small and spiky, covered in quills. And some people even say they’re cute. Now, a new study says that they are also the origin of resistance to methicillin, an antibiotic derived from penicillin. That pointed observation appears in the journal Nature.

凯伦·霍普金：这是《科学美国人》的60秒科学。我是凯伦·霍普金。

刺猬是很多东西。它们又小又尖，上面覆盖着羽毛笔。有些人甚至说他们很可爱。现在，一项新的研究表明，它们也是对甲氧西林（一种源自青霉素的抗生素）产生耐药性的根源。这一尖锐的观察结果发表在《自然》杂志上。

Antibiotic resistance is a huge clinical problem. And methicillin-resistant Staphylococcus aureus…otherwise known as M-R-S-A or MRSA…can be difficult to treat as many have developed resistance to a handful of our frontline therapeutics.

抗生素耐药性是一个巨大的临床问题。而耐甲氧西林金黄色葡萄球菌……又称为M-R-S-A或MRSA……可能很难治疗，因为许多人对我们的一线治疗药物产生了耐药性。

Jesper Larsen: Historically it has been assumed that resistance in disease-causing bacteria, including Staph aureus, is a modern phenomenon driven by clinical use of antibiotics.

杰斯珀·拉森（JesperLarsen）：历史上，人们一直认为包括金黄色葡萄球菌在内的致病细菌的耐药性是由临床使用抗生素驱动的现代现象。

Hopkin: Jesper Larsen is a senior scientist at the Statens Serum Institute in Copenhagen…

Larsen: …which is the Danish equivalent of the CDC in the US.

霍普金：杰斯珀·拉森是哥本哈根斯塔滕斯血清研究所的资深科学家…

拉森：……这是丹麦的疾病控制中心在美国的等价物。

Hopkin: Methicillin resistance was thought to be tied to prescription, in part because methicillin-resistant bugs were first isolated from British hospitals just a year after the drug became available for clinical use.

霍普金：甲氧西林耐药性被认为与处方有关，部分原因是在该药物可用于临床一年后，英国医院首次分离出了抗甲氧西林的细菌。

Larsen: But a couple of years ago we found out by chance that MecC M-R-S-A is present in more than 60 percent of hedgehogs from Denmark and Sweden.

拉森：但几年前，我们偶然发现，丹麦和瑞典60%以上的刺猬体内含有MecC M-R-S-a。

Hopkin: Ok, what’s MecC M-R-S-A? Methicillin and penicillin belong to the so-called “beta lactam” family of antibiotics. They kill bacteria by inhibiting enzymes the bugs use to build their protective cell walls. MecC…and a related gene MecA…encode versions of the enzymes that the antibiotics don’t latch onto as well.

霍普金：好的，什么是MecC M-R-s-A？甲氧西林和青霉素属于所谓的“β-内酰胺”抗生素家族。它们通过抑制细菌用来构建保护细胞壁的酶来杀死细菌。MecC…和一个相关的基因MecA…编码抗生素也不能锁定的酶的版本。

Larsen: Staph aureus bacteria that carry these genes are therefore resistant to most beta lactam antibiotics.

拉森：携带这些基因的金黄色葡萄球菌因此对大多数β-内酰胺类抗生素具有耐药性。

Hopkin: But where did these resistance genes come from? They’ve been spotted not only In folks with Staph infections, but in livestock…like pigs and cattle…and in some wild animals. And in Sweden, Larsen found that mecC is really common in hedgehogs.

霍普金：但是这些抗性基因是从哪里来的呢？不仅在感染葡萄球菌的人群中，而且在家畜中，如猪和牛，以及一些野生动物中也发现了这种细菌。在瑞典，Larsen发现mecC在刺猬中很常见。

Larsen: So the big question was, why hedgehogs carry so much mecC MRSA.

Hopkin: To find out, Larsen went to the library…

拉森：所以最大的问题是，为什么刺猬携带那么多mecC MRSA。

霍普金：为了找到答案，拉森去了图书馆…

Larsen: …where I came across an old study from the 1960s which showed that a particular fungus in hedgehogs is able to produce a penicillin-like antibiotic that is very similar to methicillin.

拉森：……我在那里看到了20世纪60年代的一项旧研究，该研究表明刺猬体内的一种特殊真菌能够产生一种类似青霉素的抗生素，这种抗生素与甲氧西林非常相似。

Hopkin: So hedgehogs with this particular skin fungus would naturally be exposed to penicillin. And that could have launched an evolutionary arms race that drove the hedgehog’s resident bacteria to evolve resistance.

霍普金：所以带有这种特殊皮肤真菌的刺猬自然会接触到青霉素。这可能会引发一场进化军备竞赛，迫使刺猬体内的细菌进化出抵抗力。

Larsen: This was a real eureka moment and led us to hypothesize that wild hedgehogs have been a natural reservoir of mecC MRSA long before penicillin and methicillin came on the market.

拉森：这真是一个大惊小怪的时刻，让我们推测，早在青霉素和甲氧西林上市之前，野生刺猬就已经是mecC MRSA的天然蓄水池。

Hopkin: To confirm this suspicion, Larsen and his colleagues screened hedgehogs from Europe and New Zealand and found that hedgehogs in Scandinavia and the UK harbor a heavy load of mecC MRSA. And they also found that the fungus carried by those hedgehogs had all the genes they needed to produce penicillin.

霍普金：为了证实这一怀疑，拉森和他的同事对来自欧洲和新西兰的刺猬进行了筛选，发现斯堪的纳维亚和英国的刺猬体内含有大量的mecC MRSA。他们还发现，这些刺猬携带的真菌具有产生青霉素所需的所有基因。

Larsen: We then went on and sequenced and analyzed the genomes of around one thousand mecC MRSA isolates. Which showed that they first appeared in hedgehogs in the early 1800s long before we started to use antibiotics in human and veterinary medicine.

拉森：然后我们继续对大约1000株mecC MRSA菌株的基因组进行测序和分析。这表明，早在我们开始在人类和兽医中使用抗生素之前，它们第一次出现在19世纪早期的刺猬身上。Hopkin: Now, that doesn’t mean that we should feel free to use antibiotics all over the place, because it’s not our fault…it’s the hedgehogs’. Because if having antibiotics around encourages bacteria to evolve resistance, taking antibiotics away robs them of their superpower…and leaves them a little bit weaker than their non-resistant kin.

霍普金：现在，这并不意味着我们应该到处使用抗生素，因为这不是我们的错……这是刺猬的错。因为如果周围有抗生素会鼓励细菌进化出耐药性，那么拿走抗生素会剥夺他们的超级能力……并让他们比没有耐药性的亲属弱一点。

Larsen: It is often very energy consuming to produce the enzymes that inactivate the antibiotics. This means that resistant bacteria will often be outcompeted by susceptible bacteria in periods when they are not exposed to antibiotics.

拉森：生产使抗生素失活的酶通常非常消耗能量。这意味着，在不接触抗生素的时期，耐药细菌往往会被易感细菌击败。

Hopkin: So if we really want to show MRSA no mercy, we should keep the methicillin to a minimum. And maybe keep at least a quills-length away from Scandinavian hedgehogs.

For Scientific American’s 60-Second Science, I’m Karen Hopkin.

霍普金：所以，如果我们真的想对耐甲氧西林金黄色葡萄球菌毫不留情，我们应该把甲氧西林控制在最低限度。也许还要离斯堪的纳维亚刺猬至少一段距离。

《科学美国人》的《60秒科学》，我是凯伦·霍普金。