An 80-year-old woman with no history of smoking developed a productive cough 8days prior to admission. Neither levofloxacin nor sulbactam/ampicillin, prescribed at the previous hospital, were effective. She was transferred to our hospital on the 8th day because she developed dyspnea and hypoxemia. On admission, she was alert and oriented. Her blood pressure was 98/57mmHg, heart rate 100beats/min, body temperature 37.0°C, respiratory rate 42/min, and oxygen saturation 98% with 6L/min of oxygen via a facial mask.