The prevailing notion is that many patients in the community will be at the lowest risk for experiencing MDR pneumonia and can be treated with a less broad anti-infective regimen. Patients with increasing exposure to the healthcare system will receive initial anti-infective therapy that is more broad in an effort to target MDROs. The investigator group believes that it is not simply exposure to the healthcare system that predicts the incidence of MDR pneumonia (i.e., criteria for HCAP), but rather, the "intensity" of exposure to the healthcare system that is predictive of MDR pneumonia. The aim of this study is to identify risk factors for MDR HCAP pneumonia in critically ill patients. .