A post-transplant infection by Nocardia cyriacigeorgica

Myasthenia gravis complicated with pulmonary infection by Nocardia cyriacigeorgica: a case report and literature review

Myasthenia gravis (MG) is an autoimmune disease. Patients with MG due to compromised autoimmune regulation, progressive muscle weakness, and prolonged use of immunosuppressants and glucocorticoid, often present with concomitant infections. However, cases of MG complicated by Nocardia infection are rare. In this case, we report MG complicated with pulmonary infection by Nocardia cyriacigeorgica. A 71-year-old male farmer who was admitted for management of MG. After 7 weeks of treatment of MG, the patient reported improvement. However, clinical presentation, inflammatory markers, and imaging findings supported a diagnosis of pulmonary infection. To further elucidate the etiology, Nocardia was identified in sputum smear microscopy and sputum culture, with 16S rRNA gene sequencing confirming N. cyriacigeorgica. The patient was prescribed trimethoprim-sulfamethoxazole. After 1 month of treatment, clinical symptoms of MG and pulmonary nocardiosis showed significant improvement. Additionally, we searched PubMed for case reports of Nocardia cyriacigeorgica pulmonary infection from 2010 to 2024 and conducted a statistical analysis of the case information. This report aims to highlights the increased risk of pulmonary Nocardia infection in MG patients after the use of steroids and immunosuppressants, thereby enhancing clinical awareness.

Metagenome next-generation sequencing plays a key role in the diagnosis and selection of effective antibiotics on the treatment of Nocardia pneumonia: a case report

Nocardia disease is an opportunistic infection, the occurrence is rare and mostly occurs in patients with immune deficiency. Even if the patient is immunocompetent, it can still be life-threatening. This case report describes a previously healthy 78-year-old male farmer with lung lesions discovered on a computerized tomography scan. Combined with the patient's history of fever and the results of elevated laboratory markers associated with inflammation, the patient was diagnosed with a lung infection. After escalating empirical broad-spectrum antibiotics, antiviral and antifungal therapy, the patient continued to deteriorate to septic shock. In the meanwhile, the patient's sputum was cultured repeatedly, and no obvious positive pathogenic bacteria were found. Considering the patient was elderly and that these lesions were solid with burr signs, as well as the progression after antimicrobial therapy cancer was considered in the differential diagnosis. Artificial intelligence (YITU, Hangzhou Yitu Medical Technology Limited Company) was also applied, and it also calculated that these lesions were cancerous. The patient received a puncture biopsy of the largest lung lesion. During the puncture pus was withdrawn from largest lung lesion. Culture and metagenome next-generation sequencing (mNGS) detection performed on pus indicated Nocardia otitidiscaviarum. The test report of the mNGS is also attached with a susceptibility report of commonly used clinical antibiotics to this Nocardia spp. Using this result, the patient's disease was quickly controlled after selecting the targeted drug compound sulfamethoxazole and intravenous meropenem for treatment. In view of the high misdiagnosis rate and poor sensitivity of culture for Nocardia spp., this case emphasized mNGS playing a key role in the diagnosis and selection of effective antibiotics for the treatment of Nocardia spp. lung infections.

Disseminated Nocardia farcinica Infection in a Renal Transplant Patient: A Case Report

Nocardia farcinica, an aerobic, Gram-positive bacterium belonging to the genus Nocardia, is a challenging opportunistic pathogen, particularly impacting immunocompromised individuals. The prevalence of human disease has witnessed a notable rise over the past two decades, correlating with an expanding population of immunocompromised individuals and advancements in the detection and identification of Nocardia spp. within clinical laboratories. This case is of a 59-year-old male with compromised immunity due to immunosuppressive medication use following a renal transplant who had an array of presentations before confirming a diagnosis of disseminated nocardiosis. The challenges faced in our case provide valuable insights into the complexities associated with diagnosing and managing Nocardia infections in immunocompromised populations, informing future clinical practice and research endeavors.