RESUMEN
Recently the incidence of Group B streptococcus (Streptococcus agalactiae) infection has been increased in nonpregnant adults, especially including the elderly and those with underlying diseases. One year ago, a 72-year-old diabetic woman underwent both total knee replacement and then received intermittently acupuncture due to both knee pain. Five days ago, she developed painful swelling on right knee joint. The synovial fluid showed leukocytosis (WBC 8,200/mm3), she was diagnosed as prosthetic joint infection, and treated with cefazolin. Her condition was rapidly aggravated despite of antibiotics therapy, open debridement and drainage was performed. But she expired due to sepsis. Both blood and synovial fluid culture yielded S. agalactiae. We reported a case of prosthetic knee joint infection caused by S. agalactiae.