Nocardia pseudobrasiliensis as an Emerging Cause of Opportunistic Infection after Allogeneic Hematopoietic Stem Cell Transplantation

Abstract

We report the case of a 55-year-old man who exhibited a nodular pneumonia 4 months after an allogeneic hematopoietic stem cell transplantation. Culture of the bronchoalveolar lavage fluid revealed Nocardia pseudobrasiliensis. This recently described carbapenem-resistant species should be included in the differential diagnosis of fungal infection in this setting. CASE REPORTWe report the case of a 55-year-old man who was admitted to our unit on 7 May 2008 for recent-onset cough and fever. His main medical history was multiple myeloma, diagnosed in February 2001. Treatment of the myeloma included several chemotherapy avenues, including two autologous stem cell transplantations, before he underwent allogeneic hematopoietic stem cell transplantation (HSCT) while in partial remission. Allogeneic HSCT from a matched, unrelated donor was performed at the end of January 2008 following conditioning with intravenous fludarabine (120 mg/m 2 ), oral busulfan (8 mg/kg of body weight), and anti-thymocyte globulin (ATG; 7.5 mg/kg). Prevention of graft-versus-host disease (GVHD) consisted of cyclosporine and mycophenolate mofetil (MMF). Interleukin-2 (IL-2) receptor monoclonal antibody (daclizumab) was added to steroids, tacrolimus, and MMF for steroid-resistant acute GVHD. He received posaconazole (200 mg three times a day) for primary prophylaxis of invasive fungal infection, oral penicillin V (2 millions units/day), and monthly aerosolized pentamidine (300 mg). At the time of admission to our department, the myeloma remained in stable partial response.Four months after allogeneic HSCT, the patient developed cough, dyspnea, and fever (38°C). On examination, he appeared asthenic; his blood pressure was 135/60 mm Hg, pulse beats were 90 per minute, respiratory rate was 20 per minute, and temperature was 38°C. Physical examination was normal.Laboratory test results were hemoglobin, 9.1 g/dl; polymorphonuclear cells, 1,700/mm 3 ; platelet count, 51,000/mm 3 ; serum creatinine, 142 mol/liter; C-reactive protein level, 69 mg/liter (normal is below 10 mg/liter); and partial O 2 pressure, 74 mm Hg.Chest radiography was normal, and a computed tomography (CT) scan of the chest revealed a spiculated nodule of the culmen (Fig. 1A).Blood cultures were negative. A serum Aspergillus galactomannan assay was negative. Because of neutropenia occurring a second time, the patient received piperacillin-tazobactam and amikacin. The neutropenia was related to valganciclovir. Bronchoscopy was macroscopically normal, and bronchoalveolar lavage (BAL) was performed; the fluid recovered contained 200 leukocytes per ml (with 64% macrophages and 34% polymorphonuclear neutrophils), with neither Pneumocystis jirovecii nor tumoral cells. Mycologic and viral examinations were negative, but direct microbiological examination of the BAL sample revealed numerous branched Gram-positive filamentous rods that fluoresced upon staining with Uvitex (optical brightener belonging to the stilbene derivatives that fluoresces upon excitation with UV light) (Fig. 2). Bacter...

Vertebral Osteomyelitis and Multiple Cutaneous Lesions in a Dog Caused by Nocardia pseudobrasiliensis

“…It is infrequently used in veterinary medicine for nocardiosis as other antibiotics are often clinically effective, and Imipenim is reserved for cases that do not respond initially to treatment. Human isolates of N. pseudobrasiliensis have been shown to be most susceptible to combination treatment of sulfa drugs and ciprofloxacin . However, susceptibility varies between reported cases, indicating the need for susceptibility testing …”

The First Korean Case of Disseminated Mycetoma Caused byNocardia pseudobrasiliensisin a Patient on Long-Term Corticosteroid Therapy for the Treatment of Microscopic Polyangiitis

“…CNS infection by a multidrug-resistant strain of N. pseudobrasiliensis was reported in an immunocompetent child. An opportunistic N. pseudobrasiliensis infection occurred in a patient with multiple myeloma, who received an allogeneic hematopoietic stem cell transplant [14, 15]. In contrast to these cases, N. pseudobrasiliensis infection, in which there is only skin involvement, such as in case of mycetoma, is rare.…”

Disseminated Nocardia pseudobrasiliensis in a Renal Transplant Recipient

“…6 In an effort to use bacterial susceptibility patterns to aid in the taxonomic grouping of Nocardia, it was noted that most of the N brasiliensis isolates involved in extracutaneous disease were resistant to minocycline. These include a fatal infection in a patient with acquired immune deficiency syndrome; 8 an immunocompetent child with ventriculitis and choroid plexitis; 9 disseminated infection in a hematopoietic stem cell transplant recipient; 10 and an elderly man with both Mycobacterium tuberculosis and N pseudobrasiliensis isolated from sputum. 3 These distinct characteristics, in addition to evidence provided by phylogenetic analysis, led to the distinction of N pseudobrasiliensis as a separate and distinct nocardial species.…”