沙門氏菌促進耐藥質粒的傳播
作者：
小柯機器人發布時間：2019/9/5 13:56:38
瑞士蘇黎世聯邦理工學院Wolf-Dietrich Hardt和Médéric Diard課題組合作，發現沙門氏菌會在腸道中促進抗生素耐藥性質粒的傳播。 相關論文2019年9月4日在線發表於《自然》。
他們研究了持留菌是否也可以促進抗性質粒的傳播。與突變相反，抗性質粒的轉移需要供體和受體細菌菌株的共同發生。為了研究該問題，研究人員選擇了兼性細胞內腸道病原體鼠傷寒沙門氏菌（S. Typhimurium）和大腸桿菌（Escherichia coli），其屬於共生微生物群。鼠傷寒沙門氏菌形成在幾種宿主組織中抗生素治療後存活的持留菌。研究顯示，組織相關的鼠傷寒沙門氏菌持久性代表質粒供體或受體的長壽儲庫。鼠傷寒沙門氏菌宿主的儲庫的形成需要腸道相關組織中的沙門氏菌致病島（SPI）-1和/或SPI-2，或系統部位的SPI-2。將這些持留菌重新接種到腸腔中使得供體與腸道駐留受體共同發生，從而有利於各種腸桿菌科菌株之間的質粒轉移。研究者在重新播種後的兩到三天內觀察到高達99％的轉接合子。數學模型顯示，罕見的再播種事件可能足以達到高頻率的共軛。在用鼠傷寒沙門氏菌口服感染以及隨後的質粒轉移後，疫苗接種減少了持留菌庫的形成。研究人員發現，即使沒有選擇質粒編碼的抗性基因，病原體持留菌的小儲庫也可以促進腸道中混雜的抗性質粒的傳播。
據了解，通過突變或獲得遺傳物質（如抗性質粒）的抗生素抗性細菌，代表了一個主要的公共衛生問題。持留菌是通過可逆地調整生理機能，存活於抗生素中的細菌亞群，並且可以促進抗生素抗性突變體的出現。
附：英文原文
Title: Salmonella persisters promote the spread of antibiotic resistance plasmids in the gut
Author: Erik Bakkeren, Jana S. Huisman, Stefan A. Fattinger, Annika Hausmann, Markus Furter, Adrian Egli, Emma Slack, Mikael E. Sellin, Sebastian Bonhoeffer, Roland R. Regoes, Mdric Diard, Wolf-Dietrich Hardt
Issue&Volume: 2019-09-04
Abstract: The emergence of antibiotic-resistant bacteria through mutations or the acquisition of genetic material such as resistance plasmids represents a major public health issue. Persisters are subpopulations of bacteria that survive antibiotics by reversibly adapting their physiology, and can promote the emergence of antibiotic-resistant mutants. We investigated whether persisters can also promote the spread of resistance plasmids. In contrast to mutations, the transfer of resistance plasmids requires the co-occurrence of both a donor and a recipient bacterial strain. For our experiments, we chose the facultative intracellular entero-pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium) and Escherichia coli, a common member of the microbiota. S. Typhimurium forms persisters that survive antibiotic therapy in several host tissues. Here we show that tissue-associated S. Typhimurium persisters represent long-lived reservoirs of plasmid donors or recipients. The formation of reservoirs of S. Typhimurium persisters requires Salmonella pathogenicity island (SPI)-1 and/or SPI-2 in gut-associated tissues, or SPI-2 at systemic sites. The re-seeding of these persister bacteria into the gut lumen enables the co-occurrence of donors with gut-resident recipients, and thereby favours plasmid transfer between various strains of Enterobacteriaceae. We observe up to 99% transconjugants within two to three days of re-seeding. Mathematical modelling shows that rare re-seeding events may suffice for a high frequency of conjugation. Vaccination reduces the formation of reservoirs of persisters after oral infection with S. Typhimurium, as well as subsequent plasmid transfer. We conclude thateven without selection for plasmid-encoded resistance genessmall reservoirs of pathogen persisters can foster the spread of promiscuous resistance plasmids in the gut.
DOI: 10.1038/s41586-019-1521-8
Source:https://www.nature.com/articles/s41586-019-1521-8