为进一步探讨屎肠球菌菌毛样结构蛋白PilA促进屎-第三军医大学学报.DOC

[基金项目] 重庆市教育委员会科技项目(KJ100311); [作者简介] 李佳俊 (1989年—), 男, 硕士研究生.主要从事抗生素和细菌耐药方面的研究。 [通讯作者] 黄文祥, 电话(023 E-mail: wenxiang_huang@163.com 屎肠球菌菌毛样结构蛋白基因pilA致病性研究 李佳俊 黄文祥* 辛小娟 佘轩 尹珍 （重庆医科大学附属第一医院感染科，重庆 400016） 【摘要】目的：研究中国屎肠球菌感染率持续上升与屎肠球菌菌毛样结构蛋白基因pilA获得的关系。方法：采用纸片扩散法对137株临床感染株行药敏试验，探讨2009年~2012年我院屎肠球菌耐药趋势。多重PCR法对临床感染株、非临床感染株行pilA、hylEfm基因检测，基因测序对阳性扩增产物进行鉴定。接合实验明确pilA、hylEfm在屎肠球菌间的传递方式。S1酶及I-CeuI酶法确认pilA、hylEfm的质粒或染色体定位。结果：137株屎肠球菌感染株中共筛查确认120株携带pilA基因，阳性率为88%，hylEfm阳性率为15%。非临床感染株中，住院患者非感染株、社区志愿者分离株pilA携带率分别为70%、52%，均未发现hylEfm携带。接合实验证实pilA、hylEfm基因均能通过质粒的接合在不同菌株间进行传递，并同时伴耐药基因传递。Southern杂交发现pilA与hylEfm可定位于同一个大质粒上，不同菌株间此质粒大小存在差异，浮动于145.5kb~291kb。结论：我院分离的屎肠球菌携带菌毛样结构蛋白pilA基因阳性率四年间居高不下，且大幅度高于非临床感染株，与近年来屎肠球菌感染率上升呈正相关。pilA、hylEfm基因可定位于同一个可移动大质粒上，此质粒在传递过程中伴随耐药基因的传递，这也许是使得屎肠球菌在医院环境中适应能力增强，成为致病优势菌的原因。 关键词：屎肠球菌；耐药性；菌毛样结构蛋白A基因；类透明质酸酶基因；质粒 Assessing the role of pilA in Enterococcus faecium Li Jiajun, Huang Wenxiang*, Xin Xiaojuan, She Xuan and Yin Zhen (Department of infectious disease,the First Affiliated Hospital,Chongqing Medical University,Chongqing 400016,China) [ABSTRACT] Objective: To investigate the relationship between pilA and the pathogenic mechanism of Enterococcus faecium. Methods: Kirby-Bauer method was used to evaluate the antimicrobial susceptibility of 137 Enterococcus faecium. A multiplex PCR was applied for the detection of hylEfm , pilA and identified by DNA sequencing. The transfer mode between strains of Enterococcus faecium via filter matings. S1 nuclease and I-CeuI assay was performed to detect the position of pilA, hylEfm gene. Results: We isolated 237 strains of Enterococcus faecium, including 137 isolates from human clinical infections, 50 isolates from stools of hospitalized patients, 50 isolates from stools of community volunteers, While 88% of clinical isolates carried pilA genes tested, 15% for hylEfm and for both. 70% of the community group isolates and 52% of animal isolates carried pilA genes, neither carried hylEfm. Filter Mati