Abstract：
Bacterial type IV secretion systems (T4SSs) are the specific devices that mediate the dissemination of antibiotic resistant genes via horizontal gene transfer (HGT). Multi-drug-resistant Enterococcus faecalis (E. faecalis) represents a clinical public health threat because of its transferable plasmid with a functional plasmid-encoded (PE)-T4SS. Here, we report a chromosome-encoded (CE)-T4SS that exists in 40% of E. faecalis isolates. Compared with the PE-T4SS, CE-T4SS displays distinct characteristics in protein architecture and is capable of mediating large and genome-wide gene transfer in an imprecise manner. Reciprocal exchange of CE-T4SS- or PE-T4SS-associated origin of transfer (oriT) could disrupt HGT function, indicating that CE-T4SS is an independent system compared with PE-T4SS. Taken together, the CE-T4SS sheds light on the knowledge of HGT in gram-positive bacteria and triggers us to explore more evolutionary mechanisms in E. faecalis.
摘要：
细菌IV型分泌系统（T4SS）是通过水平基因转移（HGT）介导抗生素抗性基因传播的特定装置。多重耐药粪肠球菌(E.粪肠）代表临床公共卫生威胁，因为其可转移的质粒具有功能性质粒编码（PE）-T4SS。这里,我们报道了一个染色体编码的（CE）-T4SS，存在于40％的粪肠球菌分离物中。与PE-T4SS相比，CE-T4SS在蛋白质结构中显示出独特的特征，并且能够以不精确的方式介导大型和全基因组的基因转移。与CE-T4SS或PE-T4SS相关的转移起源（oriT）的相互交换可能会破坏HGT功能，表明CE-T4SS与PE-T4SS相比是一个独立的系统。一起来看,CE-T4SS揭示了革兰氏阳性菌中HGT的知识，并促使我们探索粪肠球菌中更多的进化机制。
