A Rare Cause of Infection Following Total Knee Arthroplasty: Abiotrophia defectiva Linked to Recurrent Urinary Tract Infections.

Abiotrophia defectiva (A. defectiva) is a rare cause of prosthetic joint infection (PJI), and its role in surgical site infections remains unclear. A 66-year-old female developed an A. defectiva infection two years following primary right total knee arthroplasty (TKA). The patient presented with fever, knee pain, and urinary tract infection (UTI). She had a history of recurrent UTIs, likely contributing to the hematogenous spread of the pathogen. Knee aspiration was initially negative; however, subsequent cultures detected A. defectiva. The PJI was managed with surgical debridement, removal of prosthetic components, and a dynamic antibiotic spacer. We highlight the challenges associated with A. defectiva PJIs. The pathogen's fastidiousness complicates identification, and its biofilm formation on prosthetic materials makes eradication difficult. Despite its rarity, A. defectiva should be considered as a possible cause of PJIs, particularly in patients with recurrent UTIs. Early recognition and aggressive management are crucial.