- Within 48 hours prior to the first study drug administration, all patients should have the pathogens identified with appropriate specimens (e.g., sputum, tracheal aspirate, bronchoalveolar lavage [BAL], protected brushing specimen [PBS]), or should have appropriate specimens highly likely to identify the pathogens sampled. (However, the patients with Legionellosis is enrolled when the test of Legionella antigen is positive.)