Nonunion Humerous Fracture Infection Caused by Rhizobium radiobacter in a 24-Year-Old Healthy Patient: A Rare Case Report

Although Rhizobium radiobacter is a pathogen commonly found in soil and plants, human disease caused by the Rhizobium genus is rare and cited in immunocompromised patients and in those who carry foreign plastic bodies such as catheters. We present a case of a 24-year-old woman with an adequate immune system who underwent surgery for an open fracture of the right tibia and humerus due to a car accident. One year later, she was readmitted to the hospital, due to a nonunion of the humeral fracture for surgical debridement and revision of the internal fixation with iliac crest autograft. Rhizobium radiobacter was isolated from the nonunion site, and the patient was treated with intramuscular administration of amikacin for 3 weeks followed by doxycycline per os for 8 weeks. After 3 months, the patient showed complete remission of the infection, substantial improvement, and union on the X-ray images. This is the first case of Rhizobium radiobacter infection in a patient with an adequate immune system that did not carry any foreign body and probably was initially infected due to open wound exposure to soil. Treatment of R. radiobacter infections should be individualised according to the antimicrobial susceptibility test for a successful infection management.