A case report of empyema caused by Enterococcus gallinarum

Background: Enterococcus gallinarum is an infrequently intestinal symbiotic pathogen associated with nosocomial infection in immunocompromised individuals. To date, rare cases of pulmonary infection attributable to Enterococcus gallinarum were reported. Herein, we presented the first case of empyema resulting from Enterococcus gallinarum infection. Case presentation: An 81-year-old male presented with fever and dyspnea upon admission. Chest CT scan and thoracic ultrasonography confirmed the presence of right pleural effusion. Thoracoscopy revealed extensive adhesion, purulent fluid, and necrotic materials within the thoracic cavity. Enterococcus gallinarum was identified through pleural effusion culture. The patient underwent an intrathoracic injection of urokinase along with thoracic drainage. Following surgery, He took oral linezolid for over 1 month. Undergoing comprehensive treatment, the patient exhibited favorable recovery. Conclusions: Enterococcus gallinarum could traverse the impaired gut barrier and cause extraintestinal infection in the immunosuppressive host. We reported the first case of empyema due to Enterococcus gallinarum infection. It should be suspected in patients with impaired immune function and invasive therapies, without responding to conventional antibiotic treatment. Prompt diagnosis and appropriate antibiotic treatment are crucial for the outcome of patients.