# Successful Treatment of Disseminated Nocardiosis by Rapid Identification of the Organism via Genetic Analysis in a Leukemia Patient Undergoing Allogeneic Hematopoietic Stem Cell Transplantation

## TL;DR

A leukemia patient who developed widespread nocardiosis after a stem cell transplant was successfully treated after rapid genetic identification of the infection.

## Contribution

Demonstrates the successful use of genetic analysis for rapid diagnosis and treatment of disseminated nocardiosis in an immunocompromised patient.

## Key findings

- Genetic analysis identified Nocardia farcinica in a patient with multiple mass lesions.
- Prompt treatment with sulfamethoxazole, trimethoprim, and imipenem cilastatin led to improvement and no recurrence.
- Disseminated nocardiosis should be considered in immunocompromised patients with unexplained mass lesions.

## Abstract

Nocardia infections have been reported to occur in immunocompromised patients. Early diagnosis and therapeutic intervention are especially important for disseminated nocardiosis because of its high mortality rate. A case of disseminated nocardiosis after allogeneic hematopoietic stem cell transplantation, which was promptly treated after identification of the organism by genetic analysis, is presented. A 43-year-old man was diagnosed with T-cell prolymphocytic leukemia and underwent allogeneic hematopoietic stem cell transplantation. Subsequently, during long-term prednisolone administration for chronic graft-versus-host disease, he developed mass lesions throughout his body at 1033 days after transplantation. Pus culture and genetic testing of the parotid mass showed Nocardia farcinica, which improved with treatment with sulfamethoxazole, trimethoprim, and imipenem cilastatin, and there has been no recurrence. When multiple mass lesions occur after hematopoietic stem cell transplantation, and the diagnosis is difficult, disseminated nocardiosis should be included in the differential diagnosis, and appropriate laboratory testing and treatment should be performed.