Disseminated Bartonella washoensis infection in a kidney transplant recipient diagnosed by 16S rRNA next-generation sequencing: A case report

Bartonella species are increasingly recognized as causes of invasive infections in immunocompromised hosts. We report the first case in Colombia of disseminated Bartonella washoensis infection in a kidney transplant recipient. A 43-year-old woman receiving maintenance immunosuppression presented with prolonged fever, constitutional symptoms, abdominal pain, multiple splenic lesions, and vertebral osteomyelitis. Extensive microbiological, serological, and molecular investigations were initially negative. Due to persistent fever and diagnostic uncertainty, a diagnostic splenectomy was performed, which revealed necrotizing granulomas. Broad-range bacterial 16S rRNA next-generation sequencing of splenic tissue identified B. washoensis, establishing the diagnosis of disseminated bartonellosis. Targeted antimicrobial therapy resulted in clinical and radiological improvement without recurrence during follow-up. This case highlights the potential for rare zoonotic Bartonella species to cause disseminated disease in transplant recipients and underscores the diagnostic value of broad-range bacterial 16S rRNA amplicon sequencing when conventional diagnostic methods are unrevealing.