A 56-year-old female with a history of intravenous drug use, end-stage renal disease, and prosthetic mitral valve presented with back pain, fever, and leukocytosis. Initial blood cultures were negative, but subsequent cultures from a peripherally inserted central catheter grew gram-positive cocci. Echocardiogram revealed mitral valve vegetation. The pathogen was identified as Abiotrophia defectiva through 16S rRNA gene sequencing from a removed prosthetic valve. She was diagnosed with infective endocarditis and discitis, requiring prolonged antibiotic therapy and valve replacement.
Key note: Abiotrophia defectiva, a fastidious organism, can cause severe endocarditis and may require molecular methods for definitive diagnosis.