A severe case of Streptococcal pyogenes empyema following influenza A infection

Any immunological mechanisms induced by influenza virus could cause severe secondary bacterial superinfection such as those by Streptococcus pyogenes [group A streptococcus (GAS)], Streptococcus pneumoniae or Staphylococcus aureus. Over recent years, the frequency of pleural empyema has increased in children with influenza infection. We present a severe case of acute empyema caused by S.pyogenes after influenza A infection. A previously healthy 39-year old woman was diagnosed as influenza A and received oral Oseltamivir 75 mg twice daily for 5 days. She had no vaccination of influenza A. Although her influenza A infection improved, she complained of fever and cough to our institute. Chest radiography showed encapsulated pleural effusion of the left lung and pleural effusion which was consistent with acute empyema. Then, she was diagnosed as having acute empyema and was admitted to our institute. Streptococcus pyogenes was identified by pleural fluid culture on day 4. thus, MNZ was changed to clindamycin (CLDM) 600 mg three times a day. While thoracic drainage with intrapleural urokinase and combination antibiotic therapy of ceftriaxone and CLDM were performed, her general condition and chest radiographic findings were not improved. She received video-assisted thoracic debridement on day 10. After the operation, the antibiotic therapy was changed to ABPC 6 g daily iv. Due to good clinical course, the antibiotic therapy was switched to oral amoxicillin 500 mg three times daily on day 28. Then, she was discharged. Influenza A virus infection could lead to severe GAS infection, while the latter can occur in otherwise healthy individual as well. Physician must consider the possibility of severe GAS infection after influenza A infection.