[Two cases of mixed infection following 2009 H1N1 influenza pneumonia].

Case 1 was a 73-year-old woman admitted to our hospital due to bilateral pneumonia with respiratory failure. Real-time reverse transcription polymerase chain reaction (RRT-PCR) analysis confirmed 2009 H1N1 influenza infection. Streptococcus pneumoniae was confirmed from sputum culture and a urine antigen test on admission. She was treated with antiviral drugs and antibiotics, and improved gradually. Case 2 was a 66-year-old woman admitted to our hospital due to suspected acute exacerbation of interstitial pneumonitis. RRT-PCR analysis confirmed 2009 H1N1 influenza infection, and methicillin-resistant Staphylococcus aureus was cultured from her sputum. Mixed pneumonia due to influenza virus, bacteria and fungus was suspected. Although she was treated with medicines for these pathogens, she died from respiratory failure. An autopsy confirmed primary viral pneumonia, Pseudomonas aeruginosa pneumonia and invasive pulmonary aspergillosis. Not only viral pneumonia, but also mixed infections due to bacteria or fungus, might influence the prognosis of 2009 H1N1 influenza infection. These cases indicate the importance of early identification of complicating pathogens and treatment in 2009 H1N1 influenza infection.