title: Rhizobium radiobacter Endocarditis in an Intravenous Drug User: Clinical Presentation, Diagnosis, and Treatment.
abstract: Rhizobium radiobacter, a soil-based organism, is not, usually, pathogenic unless in the immunecompromised. Endocarditis, in the immunocompromised, is a typical presentation generally as a result of catheter-based infections. We describe the presentation of R. radiobacter prosthetic valve endocarditis and the inherent challenges in its presentation and diagnosis. A patient presented with acute limb ischemia secondary to R. radiobacter-mediated endocarditis and subsequent thromboembolization of the distal superior femoral and proximal popliteal arteries in the left lower limb. He underwent an uneventful thrombolectomy that restored blood flow distal to the occlusion and restored the patency of the affected arteries. Postoperatively, the patient maintained several unexplained febrile episodes. Blood cultures remained negative for infection. A cardiac work-up demonstrated the presence of vegetative growth on the prosthetic mitral and native aortic valves. Histopathologic analysis of the extracted thrombus confirmed the presence of R. radiobacter. On further history, it was elucidated that the patient was an intravenous drug user who routinely stored drug paraphernalia in plant beds. The patient recovered uneventfully after Piptazobactam was administered. R. radiobacter, and similarly other soil-based pathogens, should be considered as a potential source of endocarditic infection and thromboembolization in patients who similarly describe a history of intravenous drug use.
authors.affiliation: Department of Surgery, School of Medicine, University of Queensland, Brisbane, QLD, Australia; Department of Trauma, Royal Brisbane & Women's Hospital, Brisbane, QLD, Australia. Electronic address: bilal.zahoor@uqconnect.edu.au.
authors.forename: Bilal A
authors.initials: BA
authors.lastname: Zahoor
mesh_terms: D000328:Adult; D016960:Agrobacterium tumefaciens / Q000187:drug effects / Q000302:isolation & purification*; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D004697:Endocarditis, Bacterial / Q000175:diagnosis / Q000188:drug therapy / Q000382:microbiology* / Q000635:transmission; D016905:Gram-Negative Bacterial Infections / Q000175:diagnosis / Q000188:drug therapy / Q000382:microbiology* / Q000635:transmission; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects* / Q000295:instrumentation; D006801:Humans; D008297:Male; D008943:Mitral Valve / Q000601:surgery*; D016459:Prosthesis-Related Infections / Q000175:diagnosis / Q000188:drug therapy / Q000382:microbiology* / Q000635:transmission; D012988:Soil Microbiology; D015819:Substance Abuse, Intravenous / Q000150:complications*; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents