First Case of Bartonella henselae Bacteremia in Korea
A 73-year-old woman was admitted to our hospital for evaluation of fever. The patient had diabetes mellitus that had been managed with oral hypoglycemic agents for 10 years. Six years previously, the patient underwent an orthopedic operation involving the insertion of internal fixation due to a right ankle fracture. She had no recent history of outdoor activities or contact with pet animals. Two weeks before admission, she developed fever without any localized symptoms. One week later, the patient visited the emergency room of our hospital for evaluation of fever. At that time, her body temperature was 39℃. To identify the cause of the fever, laboratory tests were conducted, which revealed the following: hemoglobin level, 12.9 g/dL; white blood cell (WBC) count, 5,120/mm3; platelet count, 164,000/mm3; aspartate aminotransferase level, 47 IU/L; alanine aminotransferase level, 56 IU/L; alkaline phosphatase level, 228 IU/L; C-reactive protein (CRP) level, 131.6 mg/L; and erythrocyte sedimentation rate, 22 mm/h. Blood culture grew coagulase-negative staphylococcus in 1 of the 2 sets, which was dismissed as a contaminant. An abdomino-pelvic computed tomography scan revealed neither splenomegaly nor lymphadenopathies. The patient refused to be admitted to hospital; therefore, oral amoxicillin-clavulanate was prescribed. The patient was scheduled to return to the outpatient department (OPD). The patient's condition did not improve while she was at home. Thus, the patient was admitted to our division on May 22, 2009.\nOn admission, she had a body temperature of 39.0℃, a pulse rate of 90/min, a respiration rate of 18/min, and blood pressure of 120/80 mmHg. Physical examination revealed no evidence of rash, eschar, or lymphadenopathy. Her WBC count had increased to 9,930/mm3, her platelet count to 189,000/mm3, and her CRP level to 179.2 mg/L. Other laboratory results, including repeated blood culture, revealed no significant changes. To determine the cause of the headache, cerebrospinal fluid was examined, which showed no abnormal findings. Gallium and positron emission tomography scans revealed no significant abnormalities. Transesophageal echocardiography revealed mild aortic regurgitation and no vegetation on the valve. Ceftriaxone was administered empirically for 5 days, followed by a combination of ceftriaxone and doxycycline for 6 days. Administration of these antibiotics resulted in minimal clinical improvement. Owing to her persistent fever, vancomycin and doxycycline were substituted on hospital day (HD) 16, and as a result, her fever decreased to 37.5℃ the next day. On HD 23, serologic test results for Q fever, which were analyzed at the Korea Centers for Disease Control and Prevention, were positive at titers of 1:64 for immunoglobulin (Ig) M and 1:1,024 for IgG in a blood specimen taken on HD 7. The treatment regimen was changed to a combination of doxycycline and hydroxychloroquine to target the possible chronic Q fever, and the fever reduced to below 37℃. The patient was discharged on HD 29, and followed up at the OPD on July 3, 2009. At this follow-up visit, antibody titers to Q fever were 1:32 and 1:2,048 for IgM and IgG, respectively.\nWe performed cell culture or shell vial culture assays routinely for all patients with FUO. EDTA-treated whole blood (0.3 mL) obtained at admission was inoculated onto a monolayer of ECV304 cells grown in a tissue culture flask (25 cm2). The inoculated blood was washed with phosphate buffered saline 24 h later, and the culture was maintained in M199 medium (Gibco BRL, Gaithersburg, MD, USA) supplemented with 10% heat-inactivated fetal bovine serum (Gibco BRL) in a humidified atmosphere containing 5% CO2 at 37℃. Media were changed every 3 to 4 days without subculture. Three months after inoculation, certain cytopathic effects were observed (). Nine days after subculture onto a blood agar plate, small transparent colonies were observed (). To identify the isolated bacterium, conventional PCR targeting the 16S-23S rRNA intergenic spacer (ITS) region of Bartonella species was performed, followed by sequencing, as described previously []. The pair of primers used for the amplification of the ITS gene were 16SF (5'-AGAGGCAGGCAACCACGGTA-3') and 23SI (5'-GCCAAGGCATCCACC-3'). The sequence alignment of the PCR product was 960 characters long (GenBank accession number: JQ638927.1). Pair-wise comparison using BLAST (National Institutes of Health, Bethesda, MD, USA) revealed that the isolate was most like B. henselae Houston-1 strain (maximum pairwise identity score: 98%).