Empyema Caused by Mixed Infection with Streptococcus intermedius and Streptococcus constellatus in a Patient with Previous Surgery for Oral Carcinoma: A Case Report

Xingxing Zhu,1,* Jialu Chen,2,* Shengjie Wu,3 Jiling Zeng,4 Yahong Sun,1 Xiaohong Wu5 1Department of Pulmonary and Critical Care Medicine, Haining People’s Hospital, Haining, People’s Republic of China; 2Department of Gynaecology, Haining Maternal and Child Health Hospital, Haining, People’s Republic of China; 3Department of Pharmacy, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, People’s Republic of China; 4Department of Pathology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, People’s Republic of China; 5Department of Pulmonary and Critical Care Medicine, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, People’s Republic of China*These authors contributed equally to this workCorrespondence: Xiaohong Wu, Department of Respiratory and Critical Care Medicine, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, No. 3 Qingchun East Road, Shangcheng District, Hangzhou, 310000, People’s Republic of China, Tel +86 13588706901, Email [email protected]: The incidence of community-acquired empyema caused by the Streptococcus anginosus group (SAG) has been on the rise in the 2020s. To the best of our knowledge, while empyema caused individually by either strain has been reported, there are no reports on empyema caused by concurrent infection with these two strains. Here, we report for the first time empyema caused by concurrent infection with Streptococcus intermedius and Streptococcus constellatus (both SAG species) in a postoperative patient who had been treated for floor of the mouth carcinoma.Case Presentation: A 61-year-old male patient who had undergone surgical treatment for floor of the mouth carcinoma 2 year earlier suddenly presented with left-sided chest pain. Chest computed tomography (CT) revealed encapsulated pleural effusion on the left side, which was diagnosed as empyema. Metagenomic next-generation sequencing(mNGS) of the pleural fluid sample indicated mixed infection caused by Streptococcus intermedius and Streptococcus constellatus. The patient’s condition improved about 5 weeks after treatment with thoracic fluid drainage and cephalosporin antibiotics.Conclusion: This case highlights the possibility of concurrent infection with two SAG strains in patients with empyema. Currently, it is unclear whether there is a definitive relationship between a surgical history of carcinoma of the floor of the mouth and empyema caused by infection with SAG strains. This case could, perhaps, serve as a reference for future related research on the topic.Keywords: Streptococcus intermedius, Streptococcus constellatus, oral carcinoma, pleural effusion, carcinoma of the floor of the mouth, empyema