acceleration of enterococcus faecalis biofilm formation by aggregation substance expression in an ex vivo model of cardiac valve colonization加速度的粪肠球菌生物膜形成聚合物质表达贲门瓣殖民的体外模型.pdfVIP

Acceleration of Enterococcus faecalis Biofilm Formation by Aggregation Substance Expression in an Ex Vivo Model of Cardiac Valve Colonization 1 2 2 1 Olivia N. Chuang-Smith , Carol L. Wells , Michelle J. Henry-Stanley , Gary M. Dunny * 1 Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America, 2 Department of Laboratory Medicine and Pathology, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America Abstract Infectious endocarditis involves formation of a microbial biofilm in vivo. Enterococcus faecalis Aggregation Substance (Asc10) protein enhances the severity of experimental endocarditis, where it has been implicated in formation of large vegetations and in microbial persistence during infection. In the current study, we developed an ex vivo porcine heart valve adherence model to study the initial interactions between Asc10+ and Asc102 E. faecalis and valve tissue, and to examine formation of E. faecalis biofilms on a relevant tissue surface. Scanning electron microscopy of the infected valve tissue provided evidence for biofilm formation, including growing masses of bacterial cells and the increasing presence of exopolymeric matrix over time; accumulation of adherent biofilm populations on the cardiac valve surfaces during the first 2–4 h of incubation was over 10-fold higher than was observed on abiotic membranes incubated in the same culture medium. Asc10 expression accelerated biofilm formation via aggregation between E. faecalis cells; the results also suggested that in vivo adherence to host tissue and biofilm development by E. faecalis can proceed