Lymphocutaneous nocardiosis caused by Nocardia brasiliensis in an immunocompetent patient: a case report

Abstract

Nocardia usually manifests as opportunistic infections in immunocompromised hosts. Here, we report a rare case of an immunocompetent patient with lymphocutaneous nocardiosis. The patient was a 34-year-old man presenting with fever, multiple scattered pustules on both upper limbs and several subcutaneous nodules on the left elbow and forearm. Skin biopsy of the subcutaneous nodule revealed suppurative inflammation of the lymph nodes. Pus cultures were finally identified as Nocardia brasiliensis. The patient fully recovered without relapse after receiving optimized antimicrobial therapy consisting of linezolid combined with sulfonamides. Nocardiosis is a rare opportunistic disease which may be fatal and usually affects immunocompromised hosts, resulting in suppurative and granulomatous inflammation. Nocardia has a long culture cycle, is difficult to diagnose, and is more likely to be neglected in healthy young people. The present case suggests that physicians should be aware that nocardiosis is a differential diagnosis to consider in patients with suppurative infection, especially when anti-infective treatment is ineffective.

Keywords: Nocardia brasiliensis; antimicrobial therapy; immunocompetent; lymphocutaneous nocardiosis; opportunistic infection; suppurative infection.

Figure 1.

(a) Clinical features at first visit. Erythematous swelling of the right index finger was observed, accompanied by white maceration and pustules. (b) Clinical features at first visit. Erythematous swelling of the left elbow observed, accompanied by a subcutaneous nodule approximately 4 × 5 cm in size.

Figure 2.

(a) Histopathological findings. A skin biopsy taken from the largest subcutaneous abscess of the left elbow revealed a significant inflammatory cell infiltration, with abscess formation and giant cells in lymph node tissue (haematoxylin and eosin, ×200). (b) Colony culture. A small number of chalky white colonies formed on a blood agar plate. (c, d) A smear of the bacteria from a cultured colony. Gram-positive rods with long, sinuous branches were observed (Gram stain, ×1000).