Hest imaging [24]. VAP was defined as onset of pneumonia after 48 hours of mechanical ventilation, which was calculated by the sponsor from the data available in the case report form. Nosocomial pneumonia cases occurring after at least 48 hours of hospitalization that did not qualify as VAP were classified as HAP. Initially, the study only enrolled patients with pneumonias meeting these criteria. After publication of the ATS/IDSA guidelines in 2005, the study was amended to permit enrollment of patients with HCAP that did not qualify as VAP or HAP. For the trial, a slightly restrictive definition of HCAP was employed: pneumonia acquired in a long-term care or subacute/intermediate healthcare facility (e.g. nursing home, rehabilitation center); pneumonia following recent hospitalization (discharged within 90 days of current admission and previously hospitalized for 48 hours); or pneumonia in patient who received chronic dialysis care within 30 days prior to study enrollment. This trial did not enroll patients with pneumonia who only met the ATS/IDSA criteria for HCAP by virtue of having recently received home infusion therapy or wound care or of having a family member with an MDR pathogen.AssessmentsThis was a retrospective analysis of data from an international, randomized, double-blind, multicenter trial (ClinicalTrials.gov identifier NCT00084266) that compared the efficacy and safety of linezolid and vancomycin for the treatment of patients with nosocomial pneumonia and HCAP due to methicillin-resistant StaphylococcusBaseline demographic and clinical data were collected including age, sex, race, and comorbidities. Patients were required to have a baseline respiratory or sputum specimen prior to study enrollment or within 24 hours after first dose of study medication. Microbiologic cultures were performed according to the standard of care at theQuartin et al. BMC Infectious Diseases 2013, 13:561 http://www.biomedcentral/1471-2334/13/Page 3 ofstudy site, except for patients with chronic ventilation ( 30 days) or tracheostomy, for whom invasive quantitative cultures were mandated.Dantrolene Patients were followed up to 30 days from the date of study enrollment.EML4-ALK kinase inhibitor 1 In keeping with ATS/IDSA guidelines, we considered MRSA, Pseudomonas aeruginosa, and Acinetobacter spp.PMID:29844565 to be potentially MDR pathogens.Statistical analysisTable 1 Baseline characteristics of patients with HCAP, HAP, or VAPBaseline characteristic Age, y, mean (SD) Male, n ( ) APACHE II, mean (SD) Race, n ( ) HCAP (n = 199) 69.5 (13.4) 117 (58.8) 18.7 (6.4) HAP (n = 379) 63.3 (15.8) 247 (65.2) 16.1 (6.3) VAP (n = 606) 55.8 (19.8) 411 (67.8) 17.8 (5.7) 0.001 0.067 0.001 0.001 151 (75.9) 25 (12.6) 18 (9.1) 5 (2.5) 217 (57.3) 28 (7.4) 97 (25.6) 37 (9.8) 429 (70.8) 72 (11.9) 56 (9.2) 49 (8.1) 0.001 174 (87.4) 6 (3.0) 2 (1.0) 14 (7.0) 3 (1.5) 163 (43.0) 51 (13.5) 43 (11.4) 93 (24.5) 29 (7.7) 376 (62.1) 84 (13.9) 78 (12.9) 49 (8.1) 19 (3.1) p valueAll statistical tests were two-sided. To assess statistical differences in the distribution of baseline characteristics between pneumonia groups, one-way analysis of variance was used for continuous variables, and chi-square test was used for categorical variables. P values 0.05 were considered statistically significant. Statistical procedures were conducted using SAS, version 8.2 (SAS Institute, Inc., Cary, NC, USA).White Black Asian Other Region, n ( ) United States Europe Latin America AsiaResults The ITT population included 1184 adult patients.