Severe Pyothorax Caused by Streptococcus pseudoporcinus and Prevotella buccae: A Case Report

Pyothorax is a condition characterized by the accumulation of purulent pleural effusion and is often secondary to pneumonia or lung abscess. The identification of causative pathogens is essential for treatment; however, the sensitivity of pleural fluid culture remains low. We report a rare case of severe pyothorax requiring mechanical ventilation in which <i>Streptococcus pseudoporcinus</i> and <i>Prevotella buccae </i>were isolated from pleural fluid. This case highlights the potential for β-hemolytic streptococci to cause rapidly progressive and severe infections, even when rarely reported as causative organisms of pyothorax.