Influence of origin of isolates, especially endocarditis isolates, and various genes on biofilm formation by Enterococcus faecalis

Endocarditis isolates of Enterococcus faecalis produced biofilm significantly more often than nonendocarditis isolates, and 39% of 79 versus 6% of 84 isolates produced strong biofilm (P < 0.0001). esp was not required, but its presence was associated with higher amounts of biofilm (P < 0.001). Mutants disrupted in dltA, efaA, ace, lsa, and six two-component regulatory systems were largely unaltered, while disruptions in epa, atn, gelE, and fir resulted in fewer attached bacteria, as determined using phase-contrast microscopy, and less biofilm (P < 0.0001).