Which of the following organism, when isolated in the blood, requires the synergistic activity of penicillin + amino glycoside for appropriate therapy :
See the following line.
“Unlike streptococci, enterococci are not reliably killed by penicillin or ampicillin alone. Because in vitro testing has shown evidence of synergistic killing by combination of penicillin or ampicillin with an amminoglycoside, combined therapy is recommended for enterococcal endocarditis and meningitis.”

Enterococci are resistant to all cephalosporins
Enterococcus faecalis
Staph. aureus
Streptococcus pneumoniae
Bacteriodes fragilis