SFO-1是一种少见超广谱酶，仅在日本和西班牙的阴沟肠杆菌中发现，但可导致持久的医院感染暴发流行。2015年，山东报道了产SFO-1及NDM-1的多重耐药临床株，然而SFO质粒特征及传播机制尚不明了。申请人前期发现SFO阳性质粒在本地多个菌属临床株中持续存在多年，并被肺炎克雷伯菌优势克隆捕获。来自不同菌属的SFO质粒骨架结构相似，不含接合相关组件，但部分质粒能够水平传递。SFO-1基因如何完成跨菌属传播？其水平传播是否与宿主菌某些遗传特性相关？历经多年质粒进化轨迹如何？本项目拟收集本地及其它地区产SFO-1菌株，通过比较基因组学获取关键基因，采用基因敲除与回补技术研究关键基因对SFO-1基因转移的作用；通过SFO质粒骨架及耐药区特征分析、克隆特征，探索SFO-1菌株及质粒在本地长期播散的原因及进化规律，阐明 SFO-1基因的水平传递方式及播散轨迹，为医院感染控制策略提供有益建议。

SFO-1 is a low prevalent extended-spectrum beta-lactamase and was only found in Enterobacter cloacae isolates in Japan and Spain. However it can cause long-term outbreak of nosocomial infection diseases. In 2005, a multi-drug resistance isolate was recovered in Shandong provincine bearing SFO-1 and NDM-1 genes. However, it is still unclear on the characteristic of SFO-1-producing plasmids and mechanism of blaSFO-1 dissemination. We found that SFO-1-producing plasmids had been captured by many species of Enterobacteriaceae in our hospital especially by the epidemic ST11 clone of Klebsiella pneumonia. The SFO-1-producing plasmids have similar backbone and don’t contain conjugative module, though some of them are transferable. How did blaSFO spread among different species? Is it related to some characters of the host bacteria? How evolved of these plasmids? We plan to collect SFO-bearing strains in our hospital as well as other area, try to find the responsible genes for blaSFO transfer and do verification by knockout and complementation technique. We’ll analyze the characteristics of the backbones and multi-drug resistance regions of SFO-bearing plasmids and dominant clones, study on the tracking and evolution of SFO-bearing strains and plasmids and try to illustrate the mode of horizontal gene transfer which will provide helpful evidence on nosocomial infection control strategy.