Bacteremia and pleural empyema caused by Morganella morganii in an immunocompromised patient: A case report

Background: Pleural empyema is a severe condition usually caused by Streptococcus pneumoniae, Staphylococcus aureus, or enteric gram-negative bacilli. Isolation of Morganella morganii, a commensal gastrointestinal bacterium and opportunistic pathogen, is extremely rare in this context. Its intrinsic resistance to certain antibiotics and association with immunocompromised states complicates management. Case Presentation: We report the case of a 73-year-old man with multiple comorbidities, including heart failure, COPD, diabetes mellitus, and aortic valve replacement, who presented with fever, chest pain, and urinary symptoms. Imaging revealed a loculated left pleural effusion. Blood cultures and pleural fluid analysis confirmed M. morganii bacteremia and empyema. The pleural fluid was characterized by low glucose, markedly elevated LDH, and neutrophilic predominance. Initial empirical therapy failed due to intrinsic resistance, but targeted antibiotics (cefepime and ciprofloxacin) were effective. A pigtail catheter was inserted for drainage, leading to progressive improvement. The patient was discharged after 18 days of hospitalization and remained asymptomatic at follow-up.Conclusion:This case highlights the importance of considering M. morganii as a potential pathogen in pleural empyema, particularly in patients with multiple comorbidities. Early thoracentesis, microbiological identification, appropriate drainage, and targeted antibiotic therapy are crucial for favorable outcomes. Multidisciplinary management is essential in addressing rare and complicated pleural infections.