title: Clinical manifestations of pneumonia according to the causative organism in patients in the intensive care unit.
abstract: OBJECTIVE
  Whether the causative organism influences the clinical course of pneumonia in the intensive care unit (ICU) is controversial. We assessed the clinical manifestations and prognosis of pneumonia according to the causative pathogens in patients in a medical ICU.
  
  
  METHODS
  A retrospective observational study was performed in a medical ICU. Among 242 patients who were admitted to the ICU, 103 who were treated for pneumonia were analyzed.
  
  
  RESULTS
  The causative pathogen was identified in 50 patients (49.0%); 22 patients (21.6%) had multidrug-resistant (MDR) pathogens. The distribution of causative micro-organisms was Staphylococcus aureus (20%), Pseudomonas species (16%), Klebsiella pneumoniae (14%), and Acinetobacter baumannii (12%). No significant difference in ICU mortality rate, duration of ICU stay, duration of mechanical ventilation, or frequencies of re-intubation and tracheostomy were detected based on the identification of any pathogen. In sub-analyses according to the pneumonia classification, the number of pathogens identified did not differ between pneumonia types, and a higher incidence of identified MDR pathogens was detected in the hospital-acquired pneumonia group than in the community-acquired or healthcare- acquired pneumonia groups. However, the clinical outcomes of pneumonia according to identification status and type of pathogen did not differ significantly between the groups.
  
  
  CONCLUSIONS
  Neither the causative micro-organism nor the existence of MDR pathogens in critically ill patients with pneumonia was associated with the clinical outcome of pneumonia, including ICU mortality. This result was consistent regardless of the pneumonia classification.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Jung-Kyu
authors.initials: JK
authors.lastname: Lee
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Jinwoo
authors.initials: J
authors.lastname: Lee
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Young Sik
authors.initials: YS
authors.lastname: Park
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Chang Hoon
authors.initials: CH
authors.lastname: Lee
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Jae-Joon
authors.initials: JJ
authors.lastname: Yim
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Chul-Gyu
authors.initials: CG
authors.lastname: Yoo
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Young Whan
authors.initials: YW
authors.lastname: Kim
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Sung Koo
authors.initials: SK
authors.lastname: Han
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Sang-Min
authors.initials: SM
authors.lastname: Lee
mesh_terms: D000151:Acinetobacter Infections / Q000175:diagnosis / Q000382:microbiology* / Q000401:mortality / Q000628:therapy; D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D016638:Critical Illness; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007362:Intensive Care Units; D007710:Klebsiella Infections / Q000175:diagnosis / Q000382:microbiology* / Q000401:mortality / Q000628:therapy; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D018410:Pneumonia, Bacterial / Q000175:diagnosis / Q000382:microbiology* / Q000401:mortality / Q000628:therapy; D016016:Proportional Hazards Models; D011552:Pseudomonas Infections / Q000175:diagnosis / Q000382:microbiology* / Q000401:mortality / Q000628:therapy; D012121:Respiration, Artificial; D012189:Retrospective Studies; D012307:Risk Factors; D013203:Staphylococcal Infections / Q000175:diagnosis / Q000382:microbiology* / Q000401:mortality / Q000628:therapy; D013997:Time Factors; D014139:Tracheostomy; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents
keywords: Drug resistance, multiple; Intensive care units; Pathogenicity; Pneumonia