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刺猬耐药简史 刺猬拥有多重特点：它们小巧却尖锐，浑身是刺却在一些人看来甚是可爱。现在，一项新研究表示，刺猬还是一种提取自青霉素的抗生素——甲氧西林耐药性的源头。这一尖锐观点发表在《自然》（Nature）期刊上。 抗生素耐药性是一个严重的临床问题。耐甲氧西林的金黄色葡萄球菌（Staphylococcus aureus），也就是MRSA的感染难以治疗，因为许多人已经对屈指可数的一线治疗药物产生了耐药性。 “过去我们认为，包括金黄色葡萄球菌在内的致病菌耐药性是一种现代才出现的现象，由临床使用抗生素所致。” 丹麦国家血清研究所（Statens Serum Institute）的资深科学家杰斯珀·拉森（Jesper Larsen）说道。该研究所在丹麦的地位相当于美国疾病控制和预防中心（CDC）在美国的地位。 甲氧西林耐药性被认为与处方药相关，一部分原因是在该药物获得临床使用后的一年内，英国医院就率先分离了出甲氧西林耐药菌。 拉森继续说：“但几年前，我们偶然发现在丹麦和瑞典，60%以上的刺猬体内存在mecC M-R-S-A。” 什么是mecC M-R-S-A？甲氧西林和青霉素属于β-内酰胺类抗生素，细菌通过酶来构建自己的保护性细胞壁，而β-内酰胺类抗生素则通过抑制这些酶来杀死细菌。但mecC以及相关基因mecA能编码抗生素也无法破坏的酶。 “因此，携带这些基因的金黄色葡萄球菌对大部分β-内酰胺类抗生素都具有耐药性。” 但是，这些耐药性基因又从哪里来呢？它们不仅出现在感染了金黄色葡萄球菌的人体内，还出现在家畜，例如猪和牛，甚至一些野生动物体内。在瑞典，拉森发现mecC常见于刺猬体内。 “所以大问题来了……[查看全文] Hedgehogs Host the Evolution of Antibiotic Resistance 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. 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. 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. 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. 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. 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. 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. Larsen: Staph aureus bacteria that carry these genes are therefore resistant to most beta lactam antibiotics. 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. Larsen: So the big question was...[full transcript] “ Larsen, J., Raisen, C.L., Ba, X. et al. Emergence of methicillin resistance predates the clinical use of antibiotics. Nature 602, 135–141 (2022). 封面图来源：Unsplash |
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