Nocardia brasiliensis infection mimicking juvenile idiopathic arthritis in a 4-year-old girl

Septic arthritis due to Nocardia brasiliensis and a review of nocardiosis as a cause of arthritis

Bacteria of the genus Nocardia are implicated in several disease processes but are a rare cause of septic arthritis. Typically, the cause of Nocardia septic arthritis is dissemination from a pulmonary infection in an immunocompromised host. Herein we present a case of a 64-year-old male who had received a long course of prednisone for membranous nephropathy and developed a septic arthritis due to Nocardia brasiliensis. He was treated sequentially with trimethoprim-sulfamethoxazole and amoxicillin-clavulanate, linezolid and amoxicillin-clavulanate, tigecycline and amoxicillin-clavulanate, and omadacycline and amoxicillin-clavulanate. To our knowledge, only two prior cases of Nocardia brasiliensis septic arthritis without antecedent trauma to the joint or local skin breakdown have been reported. A review of the literature identified 19 other cases of Nocardia septic arthritis. This case reinforces the need to consider Nocardia infection in the differential diagnosis in the immunocompromised patient with concurrent pulmonary infection and septic arthritis.

Isolated Nocardiosis, an Unrecognized Primary Immunodeficiency?

Nocardiosis is an infectious disease caused by the gram-positive bacterium Nocardia spp. Although it is commonly accepted that exposure to Nocardia is almost universal, only a small fraction of exposed individuals develop the disease, while the vast majority remain healthy. Nocardiosis has been described as an "opportunistic" disease of immunocompromised patients, suggesting that exposure to the pathogen is necessary, but a host predisposition is also required. Interestingly, increasing numbers of nocardiosis cases in individuals without any detected risk factors, i.e., without overt immunodeficiency, are being reported. Furthermore, a growing body of evidence have shown that selective susceptibility to a specific pathogen can be caused by a primary immunodeficiency (PID). This raises the question of whether an undiagnosed PID may cause nocardiosis affecting otherwise healthy individuals. This review summarizes the specific clinical and microbiological characteristics of patients with isolated nocardiosis published during the past 30 years. Furthermore, it gives an overview of the known human immune mechanisms to fend off Nocardia spp. obtained from the study of PIDs and patients under immunomodulatory therapies.

Fulminant Nocardiosis Due to a Multidrug-Resistant Isolate in a 12-Year-Old Immunocompetent Child

Nocardiosis is a rare cause of infection that usually affects immunocompromised adult patients and might not be recognized by pediatricians. We report a fatal case of disseminated nocardiosis in a previously healthy child initially admitted for an abdominal mass with suspicion of a renal malignant tumor. The patient, originating from Mali without any medical history, displayed abdominal pain with progressive altered general status. Laboratory and imaging findings revealed lymphocytic meningitis and disseminated abscesses in the brain and the cerebellum and a large number of cystic lesions of the kidney. Despite being administered wide-spectrum antibiotics and antituberculous and antifungal therapies with an external ventricular drainage for intracranial hypertension, the patient died 6 days after his admission. Nocardia spp was cultured from a renal biopsy and the cerebrospinal fluid. Species identification and antibiotic susceptibility were obtained later, revealing a multidrug-resistant isolate of the Nocardia elegans/aobensis/africana complex. This case reveals the difficulties of diagnosing nocardiosis, in particular in children not known to be immunocompromised, because we face multiple differential diagnoses and the importance of treating nocardiosis appropriately because of intrinsic resistance issues.

Nocardia Arthritis: 3 Cases and Literature Review

Nocardia are Gram-positive filamentous bacteria responsible for infections ranging from opportunistic life-threatening disseminated diseases to chronic skin and soft-tissue infections.Even if virtually all organs can be infected, articular involvement is rare. Therefore, we report 3 recent cases and performed a literature review of cases of Nocardia arthritis in order to describe clinical features, therapeutic challenges, and outcome of these patients.Among 34 patients (31 in the literature plus our 3 cases), 21 (62%) were due to hematogenous dissemination, 9 (26%) were due to direct bacterial inoculation through the skin, and in 4 cases, the mechanism of infection was unknown. Four out of these 34 cases occurred on prosthetic joints.Whereas hematogenous infections mostly occurred in immunocompromised hosts (17 of 21, 81%), direct inoculation was mostly seen in immunocompetent patients.Eighty-two percent of patients (28 out of 34) received trimethoprim-sulfamethoxazole-containing regimens and median antibiotic treatment duration was 24 weeks (range, 12-120) for hematogenous infections and 12 weeks (range, 6-24) for direct inoculations. Outcome was favorable in 27 cases despite unsystematic surgical management (17 cases) without sequelae in 70% of the cases.Nocardia arthritis is rare but its management is complex and should rely on a combined approach with rheumatologist, infectious diseases expert, and surgeon.