<i>Corynebacterium jeikeium</i> empyema in an immunocompetent adult: first case report and literature review

<i>Corynebacterium jeikeium</i> is an uncommon but increasingly recognized cause of invasive infection, usually affecting immunocompromised patients. Empyema due to <i>C. jeikeium</i> has not been previously reported in an immunocompetent adult. We describe the first case and review the existing literature on non-diphtherial <i>Corynebacterium</i>-related empyema to highlight diagnostic and therapeutic challenges. A 26-year-old previously healthy man presented with 5 days of pleuritic chest pain, fever, and productive cough. Chest computed tomography revealed a large, loculated left pleural effusion with an air-fluid level. Initial thoracentesis yielded frank pus, confirming empyema, but the patient declined immediate drainage and was started on intravenous cefoperazone/sulbactam and moxifloxacin. His condition worsened, prompting repeat thoracentesis and catheter drainage. Culture of pleural fluid grew <i>C. jeikeium</i>, leading to a switch to intravenous vancomycin and meropenem. The patient improved rapidly, with defervescence, normalization of inflammatory markers, and complete radiographic resolution. He remained well at the 3-month follow-up. A literature review identified only four previous cases of non-diphtherial Corynebacterium-related empyema, all in patients with significant comorbidities. This case demonstrates that <i>C. jeikeium</i> can cause empyema even in immunocompetent hosts. Early microbiological diagnosis, timely pleural drainage, and appropriate antimicrobial therapy, particularly vancomycin, are critical for successful outcomes. Increased awareness and case reporting will help refine management strategies for this rare but clinically relevant pathogen.