Diversity in the composition of pleural cavity and oral cavity microbiota in different bacterial empyema

Compared with the primary empyema group, the pleural cavity microbial diversity of pneumonia complicated with empyema was significantly decreased (p < 0.05). At the phylum level, the relative abundance of Proteobacteria was significantly higher in the primary empyema group than pneumonia with empyema (p < 0.05). At the genus level, the abundance of <i>Streptococcus</i>, <i>Escherichia-Shigella</i>, and <i>Corynebacterium</i> increased in the primary empyema group, while the abundance of <i>Campylobacter</i>, <i>Salmonella</i>, <i>Bacillus</i>, and <i>Staphylococcus</i> decreased (<i>p</i> > 0.05). The shared sequences between the hydrothorax samples and mouthwash samples from the patients with empyema contributed to 94% of the total sequences used in these analyses. Correlation analysis indicated that the presence of <i>Streptococcus constellatus</i> in empyema is positively correlated with leukocytes and neutrophils, and negatively correlated with lymphocytes (<i>p</i> < 0.05).