A Rare Case of Gemella haemolysans Infection of Knee Arthroplasty.

Gemella haemolysans is a facultative, catalase-negative, anaerobic, gram-positive cocci. It is known to mostly cause endocarditis, meningitis, peritonitis, and cerebral abscesses. However, it is extremely rare for this organism to cause infections of an orthopedic nature, with only a single report of infection in total knee arthroplasty (TKA). We present a rare case of knee arthroplasty infection caused by G. haemolysans four years after an uncomplicated TKA procedure.