Esp-independent biofilm formation by Enterococcus faecalis. J Bacteriol 2004 Jan;186(1):154-63
Date
12/18/2003Pubmed ID
14679235Pubmed Central ID
PMC365672DOI
10.1128/JB.186.1.154-163.2004Scopus ID
2-s2.0-0346435112 (requires institutional sign-in at Scopus site) 231 CitationsAbstract
Enterococcus faecalis is a gram-positive opportunistic pathogen known to form biofilms in vitro. In addition, this organism is often isolated from biofilms on the surfaces of various indwelling medical devices. However, the molecular mechanisms regulating biofilm formation in these clinical isolates are largely unknown. Recent work has suggested that a specific cell surface protein (Esp) of E. faecalis is critical for biofilm formation by this organism. However, in the same study, esp-deficient strains of E. faecalis were found to be capable of biofilm formation. To test the hypothesis that Esp is dispensable for biofilm formation by E. faecalis, we used microtiter plate assays and a chemostat-based biofilm fermentor assay to examine biofilm formation by genetically well-defined, non-Esp-expressing strains. Our results demonstrate that in vitro biofilm formation occurs, not only in the absence of esp, but also in the absence of the entire pathogenicity island that harbors the esp coding sequence. Using scanning electron microscopy to evaluate biofilms of E. faecalis OG1RF grown in the fermentor system, biofilm development was observed to progress through multiple stages, including attachment of individual cells to the substratum, microcolony formation, and maturation into complex multilayered structures apparently containing water channels. Microtiter plate biofilm analyses indicated that biofilm formation or maintenance was modulated by environmental conditions. Furthermore, our results demonstrate that expression of a secreted metalloprotease, GelE, enhances biofilm formation by E. faecalis. In summary, E. faecalis forms complex biofilms by a process that is sensitive to environmental conditions and does not require the Esp surface protein.
Author List
Kristich CJ, Li YH, Cvitkovitch DG, Dunny GMAuthor
Christopher J. Kristich PhD Professor in the Microbiology and Immunology department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
Bacterial ProteinsBacteriological Techniques
Biofilms
Culture Media
Enterococcus faecalis
Fermentation
Membrane Proteins
Microscopy, Electron, Scanning
