“…The same year, it was corroborated by a large retrospective analysis of over 4,000 culture-positive episodes of pneumonia diagnosed in 59 US hospitals, finding that microbiological etiology, cost, and outcome of HCAP, using the definition of the 2005 ATS-IDSA guidelines, were more similar to hospital-acquired pneumonia (HAP) than to community-acquired pneumonia (CAP) [2]. The HCAP concept was not completely novel, however, as numerous previous studies reported that pneumonia in certain non-hospitalized patients, especially persons residing in long-term healthcare facilities and nursing homes [3], could be caused by nosocomial, gramnegative bacteria in addition to common CAP pathogens such as Streptococcus pneumoniae and Legionella pneumophila.…”