A case of severe influenza (H1N1) 2009 virus pneumonia identified by virus culture instead of PCR

: A 70-year-old man was being treated for asthma and chronic obstructive pulmonary disease, which had been well controlled. He was seen at our emergency outpatient department on October 24, 2009, for respiratory distress and mild fever. Point-of-care testing for influenza, general bacteria, and acid-fast bacilli in the sputum, were negative. With antibiotics ineffective, his respiratory status worsened, requiring him to be intubated and ventilated mechanically. Steroid pulse therapy temporarily improved his condition, as confirmed by imaging studies, but he died on hospital day 38. Polymerase chain reaction (PCR) analysis of tracheal secretion and bronchial washings collected on hospital day 14 and 21 were negative for influenza (H1N1) 2009 virus, which was identified in a subsequent culture. Negative results for reverse transcriptase-PCR analysis leave (H1N1) 2009 virus unable to be diagnosed clinically. Culture tests and repeated PCR analysis have been done in cases of strongly suspected clinical infection to confirm results. Our case, in which the virus was identified by culture, suggests that the viral load may have been too low or the time of culture inappropriate.