An empyema caused by Streptococcus constellatus in an older immunocompetent patient: Case report

RATIONALE: Empyema caused by Streptococcus constellatus is rare in patients without underlying diseases. However, the importance of the Streptococcus anginosus group, which consists of S constellatus, S anginosus, and Streptococcus intermedius, as causative organisms of empyema has been increasing. PATIENT CONCERNS: A 78-year-old man initially presented with dyspnea and chills for 4 days. He had no medical history. DIAGNOSIS: Chest X-ray and chest computed tomography showed a large and multiloculated pleural effusion with an air bubble on the right side. Cultivation of the pleural effusion using clone library analysis of the 16S rRNA gene revealed S constellatus positivity. INTERVENTIONS: The patient was treated by drainage of the pleural effusion and intravenous ceftriaxone and clindamycin for the possibility of anaerobes, followed by 10 weeks of oral antibiotics. OUTCOMES: On the 11th day of admission, the thoracic drainage tube was removed. After 1 year of treatment, there were no sequelae of empyema. LESSONS: Although S constellatus can cause serious infections in patients with underlying diseases and immunosuppression, physicians need to consider S constellatus infection in community-acquired empyema in elderly individuals. It should be treated with early pleural drainage and antibiotics to avoid surgical decortication and prolonged hospitalization.