Pneumonia was defined as the presence of new or progressive infiltrate(s), consolidation, cavitation, or pleural effusion on chest radiographs and the new onset of at least two of the following signs or symptoms: 1) cough; 2) production of purulent sputum or a change in the character of sputum; 3) auscultatory findings on pulmonary exam of crackles and/or evidence of pulmonary consolidation (dullness on percussion, bronchial breath sounds); and/or 4) the presence of acute or progressive dyspnea, tachypnea, or hypoxemia. In addition, at least one of the following criteria had to be fulfilled to establish the diagnosis of pneumonia: 1) fever, defined as body temperature > 38°C (100.4°F) taken orally; > 38.5°C (101.2°F) tympanically; or > 39°C (102.2°F