Clinical features of acute respiratory infections associated with the Streptococcus milleri group in the elderly.

The Streptococcus milleri group are becoming increasingly recognized as important pulmonary pathogens which may lead to the development of empyema or lung abscesses. Although several small series have been reported, the clinical and laboratory features of Streptococcus milleri infection have yet to be fully characterized in the elderly. We retrospectively examined the clinical features of 19 patients with Streptococcus milleri pulmonary disease who were admitted to our hospital between 2000 and 2002, based on their clinical records and laboratory data. The microbiological diagnosis was based on the results of quantitative sputum culture and other invasive procedures, including transthoracic needle aspiration or bronchoscopic examinations. There were thirteen cases of pneumonia, two of contaminant pneumonia and pleuritis, one of bronchitis, two of pulmonary abscess, and one of empyema. The patients ranged in age from 65 to 91. The most common symptoms at presentation were shortness of breath, coughing, sputum, and weight loss. An underlying disease existed in 14 of the 19 cases. We conclude that the Streptococcus milleri group is a more important cause of pulmonary infections than has been previously recognized.