Allgaier J, Lagu T, Haessler S, et al. - A large retrospective cohort analysis was conducted to evaluate the risk factors, management, and outcomes of Legionella pneumonia. This study was conducted by using 2010-2015 data from the Premier Healthcare Database. Researchers recruited individuals with a principal diagnosis code for pneumonia (or a principal diagnosis of respiratory failure or sepsis with a secondary diagnosis of pneumonia) whether they also received treatment for pneumonia by hospital day 1. They classified Legionella-tested individuals by test result, identified patient characteristics associated with testing and test result, and analyzed seasonal and regional patterns of Legionella pneumonia (LP) diagnoses. In the analysis, 43,070 (26%) were tested for Legionella, and 642 (1.5%) tested positive out of 166,689 eligible individuals. Legionella was found to be an uncommon cause of community-acquired pneumonia, occurring primarily from late spring through early autumn. The results indicated that the testing is uncommon, even among individuals with risk factors, and many positive individuals failed to receive empiric coverage for Legionella pneumonia .