The investigators will be prospectively collecting data on patients admitted to the 8300 and 8400 medical intensive care units at Barnes-Jewish Hospital requiring invasive mechanical ventilation for support in respiratory failure from pneumonia. Data will be collected on patients admitted from 1/2016-12/2016. The investigators will be collecting initial patient characteristic data as well as reviewing microbial specimen results (tracheal aspirate, bronchial alveolar lavage, viral multiplex, blood cultures) and antibiotic usage in real time. The investigators will identify any changes in antibiotic usage demonstrated with the advising of the ICU antibiotic stewardship team.