title: Treatment of Rhizobium radiobacter bacteremia in a critically ill trauma patient.
abstract: OBJECTIVE
  To report the first case of Rhizobium radiobacter bacteremia in a critically ill trauma patient.
  
  
  METHODS
  A 36-year-old female trauma patient hospitalized at The Regional Medical Center at Memphis developed bacteremia due to Rhizobium radiobacter on hospital day 9. The central line catheter tip culture from the same hospital day was negative. No source for the R radiobacter bacteremia was identified. Empirical and definitive antibiotic therapy consisted of cefepime 2 g intravenously every 8 hours for at total of 8 days. On completion of antibiotics, the patient demonstrated clinical resolution by immediate defervescence and gradual normalization of her white blood cell count. She demonstrated microbiologic success of therapy with negative blood cultures on hospital days 22, 34, 45, and 61. She was discharged on hospital day 80.
  
  
  CONCLUSIONS
  Rhizobium species are common soil and plant pathogens that rarely cause infections in humans. Previous reports of Rhizobium infections have been in immunocompromised patients; generally those with cancer or HIV infection. Intravenous catheters have commonly been cited as the source of infection. The trauma patient in this case constitutes a unique presentation of R radiobacter bacteremia when compared with other case reports. Her indwelling catheter was not the source of her infection, and her only identifiable risk factor for R radiobacter infection was hospitalization. However, she did possess potential reasons for development of an infection with an unusual organism such as R radiobacter. Potential immune modulating therapies included blood transfusions, opioid analgesics, benzodiazepines, general anesthetics, and surgical procedures. Finally, trauma itself has been associated with some degree of immunosuppression. All these issues may have placed the patient in this case at risk of an opportunistic infection like R radiobacter.
  
  
  CONCLUSIONS
  Based on this case, R radiobacter may be considered a potential pathogen causing bacteremia in critically ill trauma patients.
authors.affiliation: University of Tennessee Health Science Center, Memphis, TN, USA.
authors.forename: Supriya
authors.initials: S
authors.lastname: Ponnapula
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Swanson
authors.forename: G Christopher
authors.initials: GC
authors.lastname: Wood
authors.forename: Bradley A
authors.initials: BA
authors.lastname: Boucher
authors.forename: Diana L
authors.initials: DL
authors.lastname: Wells
authors.forename: Martin A
authors.initials: MA
authors.lastname: Croce
authors.forename: Timothy C
authors.initials: TC
authors.lastname: Fabian
mesh_terms: D000328:Adult; D016960:Agrobacterium tumefaciens / Q000187:drug effects* / Q000302:isolation & purification; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D016470:Bacteremia / Q000097:blood / Q000188:drug therapy* / Q000276:immunology / Q000382:microbiology; D000077723:Cefepime; D002511:Cephalosporins / Q000008:administration & dosage / Q000627:therapeutic use*; D016638:Critical Illness; D005260:Female; D006801:Humans; D009894:Opportunistic Infections / Q000097:blood / Q000188:drug therapy* / Q000276:immunology / Q000382:microbiology; D016896:Treatment Outcome; D014947:Wounds and Injuries / Q000097:blood / Q000188:drug therapy* / Q000276:immunology / Q000382:microbiology
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D000077723:Cefepime
keywords: Rhizobium spp; bacteremia; critical care; infectious disease; trauma