Cerebral nocardiosis after allogeneic bone marrow transplantation

Nocardia infections in solid organ transplantation: Guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of Nocardia infections after solid organ transplantation (SOT). Nocardia infections have increased in the last two decades, likely due to improved detection and identification methods and an expanding immunocompromised population. The risk of developing nocardiosis after transplantation varies with the type of organ transplanted and the immunosuppression regimen used. Nocardia infection most commonly involves the lung. Disseminated infection can occur, with spread to the bloodstream, skin, or central nervous system. Early recognition of the infection and initial appropriate treatment is important to achieve good outcomes. Species identification and antimicrobial susceptibility testing are strongly recommended, as inter- and intraspecies susceptibility patterns can vary. Sulfonamide is the first-line treatment of Nocardia infections, and combination therapy with at least two antimicrobial agents should be used initially for disseminated or severe nocardiosis. Trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis may be helpful in preventing Nocardia infection after SOT.

Nocardiosis of the central nervous system: experience from a general hospital and review of 84 cases from the literature

Central nervous system (CNS) nocardiosis is a rare disease entity caused by the filamentous bacteria Nocardia species. We present a case series of 5 patients from our hospital and a review of the cases of CNS nocardiosis reported in the literature from January 2000 to December 2011. Our results indicate that CNS nocardiosis can occur in both immunocompromised and immunocompetent individuals and can be the result of prior pulmonary infection or can exist on its own. The most common predisposing factors are corticosteroid use (54% of patients) and organ transplantation (25%). Presentation of the disease is widely variable, and available diagnostic tests are far from perfect, often leading to delayed detection and initiation of treatment. The optimal therapeutic approach is still undetermined and depends on speciation, but lower mortality and relapse rates have been reported with a combination of targeted antimicrobial treatment including trimethoprim/sulfomethoxazole (TMP-SMX) for more than 6 months and neurosurgical intervention.

Central nervous system infections in cancer patients and hematopoietic stem cell transplant recipients

Central nervous system (CNS) infections in cancer patients present a diagnostic and therapeutic challenge for clinicians. While CNS infections are not frequent complications of cancer, its therapies, or hematopoietic stem cell transplantation, the importance of CNS infections lies in their propensity to result in profound morbidity and substantial mortality in this vulnerable patient population. With an expanding population of patients with malignant disease undergoing more potent and aggressive therapies and with the advent of newer immunomodulatory agents, the incidence of CNS infectious complications is likely to rise. This chapter will summarize the clinical and diagnostic evaluation of potential infections of the CNS in these patients and will discuss particular pathogens of interest with regard to this at-risk patient population.

Fungal CNS infections in patients with hematologic malignancy

Various fungal agents can cause CNS infections. CNS fungal infections may present as a mass (i.e., brain abscess) typically in the course of aspergillosis or zygomycosis, or may primarily involve the meninges (i.e., meningitis), as can be observed in patients with candidiasis or cryptococcosis. Most commonly, fungal brain abscesses are due to aspergillosis. CNS aspergillosis is observed particularly in acute leukemia and allogeneic hemopoietic stem cell transplantation patients. Usually, aspergillosis is localized in the lungs and secondarily spreads to the brain; only in few cases does it develop as solitary localization of CNS. In these conditions, diagnosis is very difficult because signs and symptoms can be completely aspecific. Diagnosis can often be performed only through aggressive procedures (i.e., stereotactic puncture). Zygomycetes are the second most frequent cause of brain abscesses. CNS involvement is higher than in the course of invasive aspergillosis, and this fungal complication is also characterized by a high mortality rate. In vitro and in vivo studies demonstrated that only posaconazole and lipid formulations of amphotericin B present some possibility of success in the treatment of zygomycosis, but the pharmacologic approach should always be associated with surgery. Among molds, other agents (i.e., Fusarium and Scedosporium) may also be responsible for fungal abscess. More rarely during the course of a hematologic malignancy, a meningeal candidiasis or cryptococcosis may be observed. This review mainly focuses on the epidemiology, clinical manifestations, diagnosis and management strategies of all cases of CNS fungal infections in hematologic patients.