自然界中耐抗生素细菌的起源

An evolutionary battle between fungi and bacteria on hedgehogs' skin gave rise to a type of antibiotic-resistant bacteria long before humans started using the antibiotics that were thought to lead to such superbugs, a new study reveals.

一项新的研究显示，早在人类开始使用抗生素之前，真菌和细菌在刺猬皮肤上的一场进化之战就产生了一种耐抗生素细菌，人们认为这种抗生素会导致超级细菌。

Researchers traced some lineages of the superbug MRSA, or methicillin-resistant Staphylococcus aureus, to a parasitic fungus found on the skin of European hedgehogs (Erinaceus europaeus).

研究人员追踪了超级细菌MRSA或耐甲氧西林金黄色葡萄球菌的一些谱系，并发现欧洲刺猬皮肤上的一种寄生真菌(Erinaceus europaeus)。

The fungus secretes antibiotics to fight and kill Staphylococcus aureus bacteria (also found on hedgehogs); to stay alive, the bacteria, in turn, evolved antibiotic resistance that later crossed into livestock and humans, the research team reported in a new study.

这种真菌会分泌抗生素来杀死金黄色葡萄球菌;研究小组在一项新研究中报告说，为了生存，细菌反过来进化出抗生素耐药性，后来又传到了牲畜和人类身上。

While the use of antibiotics often drives the evolution of superbugs, this study shows the origins of some antibiotic-resistant bacteria in nature.

虽然抗生素的使用通常会推动超级细菌的进化，但这项研究揭示了自然界中耐抗生素细菌的起源。

"We know the resistance genes got into pathogen genomes before humans were using antibiotics, but this really describes a mechanism of how that might happen," study co-author Ewan Harrison, a researcher at the University of Cambridge and the Wellcome Sanger Institute in the U.K., told Live Science.

“我们之前知道耐药基因在人类使用抗生素之前就进入了病原体基因组，但现在确实描述了一种可能的发生机制。”该研究的合著者、剑桥大学和威尔康桑格研究所的研究员伊万·哈里森说。

MRSA is a strain of staph bacteria that resists antibiotics and is therefore harder to treat if it gets into the body of humans or livestock and causes disease. The researchers investigated mecC-MRSA, a relatively rare form of the superbug that's responsible for about 1 in 200 human MRSA infections, according to a statement released by the University of Cambridge.

MRSA 是一种抗抗生素的葡萄球菌菌株，因此如果它进入人类或牲畜的身体并引起疾病，则更难治疗。根据剑桥大学发布的一份声明，研究人员调查了 mecC-MRSA，一种相对罕见的超级细菌，每200例人类 MRSA 感染中就有1例会感染这种细菌。

The mecC-MRSA was discovered in 2011 and was thought to have emerged in cows given large amounts of antibiotics. However, previous research has also found that up to 60 percent of European hedgehogs carry it. The hedgehogs' fungus, Trichophyton erinacei, creates its own penicillin antibiotics naturally to fight off bacteria.

mecC-MRSA于2011年被发现，并被认为是在服用大量抗生素的奶牛身上出现的。然而，此前的研究也发现，高达60%的欧洲刺猬携带这种病毒。刺猬的真菌，毛癣菌，会创造出自己的青霉素抗生素来对抗细菌。

Harrison was part of an international research team that sequenced genomes of the parasitic fungus on the hedgehogs and found the genes responsible for producing the penicillin antibiotics that kill staph bacteria.

哈里森是一个国际研究小组的成员，该小组对刺猬身上的寄生真菌进行了基因组测序，并发现了产生杀死葡萄球菌的青霉素抗生素的基因。

They then sequenced the bacteria and dated the penicillin-resistant genes by measuring the number of certain mutations in the genome that are known to occur at a fixed rate each year and counting backward, according to Harrison.

根据哈里森的说法，他们随后对细菌进行测序，并通过测量基因组中已知每年以固定速率发生的某些突变的数量，然后倒推出青霉素耐药基因的年代。

They found that the bacteria had resistance to methicillin, a form of penicillin, in the 1800s, long before the clinical use of penicillin began in the 1940s.

早在19世纪，他们就发现这种细菌对青霉素的一种形式甲氧西林具有耐药性，而青霉素的临床应用早在20世纪40年代就开始了。

The researchers think this type of MRSA probably first evolved in hedgehogs, though they aren't sure how mecC-MRSA crossed into humans.

研究人员认为这种耐甲氧西林金黄色葡萄球菌可能首先在刺猬身上进化，尽管他们不确定mecC-MRSA是如何进入人类体内的。

"We know that these resistance genes exist in the soil and soil bacteria, and animals like hedgehogs and other wildlife obviously have much more contact with soil on a day-to-day basis than most of us do," Harrison said.

“我们知道这些抗性基因存在于土壤和土壤细菌中，刺猬和其他野生动物与土壤的日常接触显然比我们大多数人都要多。”哈里森说。

The superbug could have jumped to humans through direct contact with hedgehogs, the authors said. Harrison stressed, however, that people shouldn't fear hedgehogs for this reason.

作者说，这种超级细菌可能通过与刺猬的直接接触而跳到人类身上。然而，哈里森强调，人们不应该因为这个原因害怕刺猬。

"I don't think hedgehogs are a risk," Harrison said. "I think that's important to get across." The mecC-MRSA is also found in livestock, so these animals, or another unidentified animal, may have been intermediaries.

“我不认为刺猬是一种风险，”哈里森说，“认清这一点很重要。” mecC-MRSA 也存在于牲畜中，因此这些动物或其他身份不明的动物可能是中间媒介。

"It just shows evolutionary processes in nature can select for antibiotic resistance and that can end up in a human pathogen," Harrison said.

“它只是表明自然界的进化过程可以选择抗生素耐药性，而这最终可能会导致侵害人类的耐药病原体出现。”哈里森说。

The findings were published Wednesday (Jan. 5) in the journal Nature.

这项研究结果发表在周三(1月5日)的《自然》杂志上。