Metagenomic Next-Generation Sequencing for the Diagnosis of Trichomonas Vaginalis-Associated Empyema: a Case Report and Literature Review.

Abstract

BACKGROUND: This report describes a rare case of empyema caused by Trichomonas vaginalis co-infected with Streptococcus agalactiae and Streptococcus pyogenes, aiming to explore the role of T. vaginalis in the development of empyema, its diagnostic methods, and treatment strategies. METHODS: The patient was a 46-year-old male who presented with cough, sputum production, and shortness of breath. The diagnosis was made using chest CT, routine pleural fluid analysis, bacterial culture, and metagenomic next-generation sequencing (mNGS). Pleural fluid examination revealed numerous motile Trichomonas organisms, and bacterial culture identified Streptococcus agalactiae and Streptococcus pyogenes as the pathogens. Fur-ther mNGS confirmed these bacteria as the causative agents, with 39 Trichomonas sequences detected, including 32 sequences specific to T. vaginalis. RESULTS: The patient received combination antimicrobial therapy and underwent chest tube drainage and thoracoscopic empyema debridement. Post-treatment, the patient's condition significantly improved. A literature review revealed that while Trichomonas tenax is a common pathogen in empyema, T. vaginalis is an extremely rare cause. T. vaginalis infection may be associated with bacterial co-infections, immunosuppression, or poor hygiene. CONCLUSIONS: This case is the first report of T. vaginalis induced empyema, expanding the understanding of Trichomonas infections. Although such infections are rare, they should be considered in high-risk patients. Further studies are needed to investigate the infection pathways of T. vaginalis and its mechanisms of bacterial synergy in disease pathogenesis to improve clinical diagnosis and treatment strategies.