Invasive Nocardiosis Versus Colonization at a Tertiary Care Center: Clinical and Radiological Characteristics.

Area of Science:

• Medical Microbiology
• Infectious Diseases
• Pulmonology

Background:

• Nocardia species are aerobic actinomycetes that can cause opportunistic infections.
• Differentiating between Nocardia colonization and invasive disease is critical for appropriate patient management.
• Clinical and radiographic findings can aid in distinguishing these two conditions.

Purpose of the Study:

• To describe the clinical and radiographic findings in patients with positive Nocardia cultures.
• To emphasize the differences between invasive Nocardia disease and Nocardia colonization.

Main Methods:

• A retrospective cohort study was conducted.
• 133 patients with positive Nocardia isolates and chest CT scans were analyzed.
• Data on clinical presentation, comorbidities, and imaging findings were collected.

Main Results:

• Patients with Nocardia colonization were older and more frequently had chronic obstructive pulmonary disease and coronary artery disease.
• Invasive nocardiosis patients had more comorbidities like diabetes and chronic kidney disease, and presented with fever, cutaneous lesions, and fatigue.
• Chest CT revealed distinct nodule distribution patterns: diffuse in invasive disease and peribronchiolar in colonization.

Conclusions:

• Isolation of Nocardia from sputum does not automatically indicate active infection.
• Combining clinical and chest CT findings is essential for differentiating invasive nocardiosis from Nocardia colonization.