A 64-year-old female was diagnosed with adult T-cell leukemia/lymphoma (ATLL), which became clinically overt as acute and lymphoma type 4 months prior to a bone marrow transplantation (BMT). She first received a modified LSG15 regimen 8, with three intensified and alternating regimens of VCAP (vincristine, cyclophosphamide, doxorubicin, and prednisolone), AMP (adriamycin, MCNU, and prednisolone), and VECP (vindesine, etoposide, carboplatin, and prednisolone), followed by anti-CCR4 antibody, which led to a good partial response. The patient had undergone an unrelated BMT following a reduced-intensity preparation regimen (RIST) consisting of fludarabine 25 mg/m2 for 5 days and busulfan 0.8 mg/kg x4/day for 4 days, and 2 Gy total body irradiation (TBI). With combined tacrolimus and short-term methotrexate (MTX) as graft-versus-host disease (GVHD) prophylaxis, she achieved engraftment uneventfully on day 19.
On day 50, a routine cytomegalovirus (CMV) antigenemia testing converted to positive, and we initiated treatment with valganciclovir (valGCV) 180 mg/day orally. This preemptive therapy 9 was effective, and the CMV antigenemia disappeared on day 70. On day 61, the patient's course was complicated with HHV-6 encephalopathy, with a sudden-onset consciousness disturbance progressing over a 12-h span. The diagnosis of HHV-6 encephalitis was made based on the detection of HHV-6 DNA 2.0 x 105 copies/mL in the patient's cerebrospinal fluid (CSF) the following day (day 62). As soon as the encephalitis was diagnosed, we switched the valGCV to foscarnet 60 mg/kg, twice a day. On day 84, a cranial MRI scan showing diffuse high intensity on the limbic system confirmed the diagnosis of HHV-6 encephalitis.
Despite the antiviral therapy, systemic convulsions impaired the patient's pulmonary condition, and she required mechanical ventilator support on day 65. She was intermittently febrile beginning 1 day after intubation (day 66). Her neutrophil count was 6895/muL at the onset of the febrile episode, indicating the fever was not neutropenic. We started meropenem (0.5 g, every 8 h) empirically. A tracheotomy was performed on day 79. On day 82, a chest X-ray showed an infiltration shadow on bilateral lungs, and the patient's condition deteriorated to extensive acute respiratory distress syndrome (ARDS) within 3 days (day 85) (Fig. 1). Sputum collected from the intratracheal tube on day 78 revealed C. indologenes. Sputum was suppurative (Miller & Jones classification P3), and Geckler classification was 5. No other antimicrobial-resistant organisms were recovered from her sputum. She underwent tazobactam/piperacillin as antimicrobial target therapy and meropenem as an empirical treatment, but died of pneumonia (respiratory failure) due to C. indologenes on day 91. The antimicrobial susceptibilities of the patient's isolate are listed in Table 1.