Extensor tenosynovitis and subcutaneous abscess caused by hypervirulent Klebsiella pneumoniae.

We report a rare case of invasive Klebsiella pneumoniae infection in a previously healthy 52-year-old Japanese man who presented with extensor tenosynovitis associated with subcutaneous abscess of the right hand, in the setting of concomitant liver and prostatic abscesses. Cultures from blood, liver abscess aspirate, synovial fluid and aspirate from the subcutaneous tissue of the hand all grew K. pneumoniae. Although genomic biomarker testing was not available, a positive string test along with the characteristic clinical presentation suggested a hypervirulent phenotype. Surgical debridement of the hand and targeted antimicrobial therapy led to clinical improvement. This case underscores the importance of considering hematogenous dissemination in cases of tenosynovitis without a history of trauma and highlights the protean manifestations of hypervirulent K. pneumoniae.