Empyema Due to Listeria monocytogenes in a Patient With Rheumatoid Arthritis

Listeria monocytogenes is an uncommon cause of pleural empyema, particularly in patients with rheumatoid arthritis (RA). Disease and treatment-related immunosuppression increases susceptibility to invasive listeriosis, which carries significant mortality. A 78-year-old man with seropositive RA treated with methotrexate and low-dose corticosteroids presented with fever, hypotension, pleuritic chest pain, and weakness. Laboratory tests showed leukocytosis, neutrophilia, and elevated C-reactive protein. Imaging revealed a left pleural effusion with lower-lobe collapse. Thoracentesis drained 800 mL of exudative fluid, and cultures of pleural fluid and blood isolated L. monocytogenes. Cranial CT and lumbar puncture performed due to neurological symptoms were normal. High-dose ampicillin plus cotrimoxazole was administered for 7 days, followed by ampicillin monotherapy to complete a total of 14 days of antibiotic treatment, achieving progressive clinical and radiological improvement. Empyema caused by L. monocytogenes is rare and occurs mainly in immunocompromised hosts, with only isolated cases described in RA. This case underscores the need to consider Listeria infection in immunosuppressed RA patients presenting with pleural empyema.