Pneumonia and pleural effusion. Association with influenza A virus and Staphylococcus aureus.

An 8-month-old infant with severe pneumonia and massive pleural effusions was found to have concurrent infections due to Staphylococcus aureus and influenza A virus. This was proved by the isolation of both agents from the pleural fluid. We believe this is the first case of isolation of an influenza virus from pleural effusions.