Abstract

Background: Streptococcus constellatus is a member of Streptococcus anginosus group (SAG) that tends to cause pyogenic infections in various cavities. However, Streptococcus constellatus is not easily detected as a pathogen in the routine laboratory tests. As a member of SAG, it is the rarest to cause severe infections, which lead to ICU hospitalization. This case report adds valuable information to the current body of knowledge of these infective diseases.

Case presentation: A 61-year-old woman was admitted to the hospital due to fever, chest pain and shortness of breath for 1 week. Chest x ray showed right-sided pleural effusion and an irregularly shaped cavity with an air-fluid level, so the patient underwent open thoracotomy and decortication surgery for open drainage. 2 chest tubes were inserted, and purulent fluid was aspirated. Postoperatively, the patient remained intubated due to septic profile and was admitted to the ICU. Intravenous broad-spectrum antibiotics were used. The routine etiological examinations of the pleural effusion were all positive and detected Streptococcus constellatus. On the 3^rd day of ICU stay, the patient deteriorated, and the surgical site showed signs of infection. A subsequent chest CT showed patchy opacities with air bronchogram, a new cavity on the outside of the postoperative lesions (possible relapse of previously treated abscess) and subcutaneous emphysema. Deep vein thrombosis in the left internal jugular vein was also confirmed in the chest CT. The patient underwent a 2^nd surgery and PDR A.baumanii was detected and treated with targeted intravenous antibiotics. The patient recovered and was dismissed from hospital after 41 days of hospitalization.

Conclusions: We reported a case of pyopneumothorax secondary to Streptococcus constellatus infection, which was identified by bacterial culture. This case highlights the SAG group members’ potential of causing rare severe infections in the respiratory system and how important is early surgical approach in combination with intravenous antimicrobial treatment on the clinical outcome.