Triple-drug antibiotic therapy for disseminated nocardial abscess in the mediastinum and brain of an immunocompetent patient: a case report

Background Nocardia are widely present in nature and considered opportunistic pathogens. First discovered by Edmond Nocard in 1888, they are gram-positive aerobic bacteria belonging to the class of Actinomycetes, an order of rod-shaped bacteria. Nocardia can result in hematogenous spread infection through the ruptured skin or respiratory tract when the host's immune system is compromised. Currently, 119 species of Nocardia have been identified, with 54 capable of causing infections in humans. Nocardial brain abscesses are a rare intracranial lesion, accounting for only 2% of all brain abscesses. This article reports a successfully cured case of mediastinal Nocardia infection with disseminated brain abscess. The patient was initially admitted with suspected brain metastasis from lung cancer. The purpose of this report is to provide insight into the diagnosis and treatment of this disease. Case presentation The patient presented with intermittent chills, shivering, and fever, with the highest temperature of 39˚C, accompanied by shoulder and back pain, dizziness, and headaches. A chest-enhanced computed tomography (CT) revealed multiple enhanced nodulars in the bilateral hilum and mediastinum. A head-enhanced CT revealed scattered multiple ring-enhanced nodules in both cerebral hemispheres and the left cerebrum, accompanied by extensive surrounding edema. The mediastinal puncture tissue culture confirmed the growth of Nocardia . After a thorough multidisciplinary discussion (MDT) to rule out the possibility of mediastinal and intracranial metastatic tumors, we promptly initiated treatment with a three-drug antibiotic regimen consisting of imipenem/cilastatin sodium, linezolid dextrose, and Trimethoprim-sulfamethoxazole (TMP-SMX). The patient ultimately achieved complete remission. Conclusions People engaged in agricultural work should be alert to central nervous system infection caused by Nocardia and brain metastatic tumors for identification. Typical imaging findings contribute to the early diagnosis of nocardial abscesses. Vital for prompt treatment.