title: Bacteremia due to Citrobacter braakii: A case report and literature review.
abstract: Among the Citrobacter genus, the most commonly isolated bacteria from human specimens are Citrobacter freundii and Citrobacter koseri, and previous cases of infection due to Citrobacter braakii have been rarely reported. We present a case of bacteremia due to C. braakii in a 38-year-old woman with cervical cancer. She was admitted to our hospital with complaints of a fever, chills, and nausea. Blood culture results showed gram-negative bacilli identified as C. braakii via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis, although biochemical testing findings were suggestive of C. freundii. Since a rare pathogen was detected in the present case and the results of additional biochemical studies were suggestive of both C. braakii and Citrobacter farmeri, genetic analysis was conducted. Finally, the gram-negative bacilli were confirmed as C. braakii, a member of the C. freundii complex since 1993, by 16S ribosomal RNA gene sequencing analysis. The gastrointestinal tract was considered the portal of entry, because the patient had a rectal fistula and other cultures such as urine and vaginal discharge incubated species other than C. braakii. The patient recovered after receiving treatment with ciprofloxacin for 14 days. The epidemiology and clinical characteristics of C. braakii infection are still unknown because of the limitations in accurate identification by using currently available commercial biochemical testing and previously, only 6 cases of C. braakii infection have been reported. Physicians should focus on this species, because it causes community-acquired infections, although further studies are needed to clarify the clinical characteristics of C. braakii infections.
authors.affiliation: Department of Infectious Diseases, Respiratory, and Digestive Medicine, Control and Prevention of Infectious Diseases, Faculty of Medicine, University of the Ryukyus, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Hirai
authors.affiliation: Department of Infectious Diseases, Respiratory, and Digestive Medicine, Control and Prevention of Infectious Diseases, Faculty of Medicine, University of the Ryukyus, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Uechi
authors.affiliation: Department of Infection Control and Prevention, Aichi Medical University Hospital, Japan.
authors.forename: Mao
authors.initials: M
authors.lastname: Hagihara
authors.affiliation: Department of Infection Control and Prevention, Aichi Medical University Hospital, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Sakanashi
authors.affiliation: Department of Infectious Diseases, Respiratory, and Digestive Medicine, Control and Prevention of Infectious Diseases, Faculty of Medicine, University of the Ryukyus, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kinjo
authors.affiliation: Department of Infectious Diseases, Respiratory, and Digestive Medicine, Control and Prevention of Infectious Diseases, Faculty of Medicine, University of the Ryukyus, Japan. Electronic address: f014936@med.u-rukyu.ac.jp.
authors.forename: Shusaku
authors.initials: S
authors.lastname: Haranaga
authors.affiliation: Department of Infectious Diseases, Respiratory, and Digestive Medicine, Control and Prevention of Infectious Diseases, Faculty of Medicine, University of the Ryukyus, Japan.
authors.forename: Jiro
authors.initials: J
authors.lastname: Fujita
mesh_terms: D000328:Adult; D016470:Bacteremia / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology*; D002954:Citrobacter / Q000187:drug effects / Q000302:isolation & purification*; D004756:Enterobacteriaceae Infections / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology*; D005260:Female; D041981:Gastrointestinal Tract / Q000382:microbiology; D006801:Humans
keywords: 16S rRNA; Bacteremia; Citrobacter braakii; Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis