Enterococcus faecalis is a gram-negative bacterium that causes nosocomial infections as well as infections of the GI tract and root canals. It ferments glucose but does not produce catalase, and can cause diseases such as bacteremia, endocarditis, periodontitis, meningitis, UTIs, and wound infections. Enterococcus faecalis is resistant to some antibiotics but sensitive to others, so combined drug therapy is often used to treat infections.

1. Enterococcus faecalis
Enterococcus faecalis is gram-negative bacteria which is the
cause of nosocomial infections. It also causes infection of GI
track and also the cause of RCT infection in dental practices.
A slide showing it is gram negative
It can ferment glucose and is negative to catalase reaction
which is done to check H2O2 hydrolysis by a bacterium using the
enzyme catalase. If bacteria have catalase enzyme, they show
this reaction which indicate they are catalase positive.

2. Diseases caused by enterococcus faecalis includes bacteremia,
endocarditis, periodontitis, meningitis, UTI and wound
infections.
It is resistant to certain antibiotics and can show sensitivity to
some. Thus, combined drug therapy usually helps in better
treatment.
Full Resource about enterococcus faecalis here