title: Pseudomonas aeruginosa serotypes in nosocomial pneumonia: prevalence and clinical outcomes.
abstract: BACKGROUND
  Pseudomonas aeruginosa frequently causes nosocomial pneumonia and is associated with poor outcome. The purpose of this study was to assess the prevalence and clinical outcome of nosocomial pneumonia caused by serotype-specific P. aeruginosa in critically ill patients under appropriate antimicrobial therapy management.
  
  
  METHODS
  A retrospective, non-interventional epidemiological multicenter cohort study involving 143 patients with confirmed nosocomial pneumonia caused by P. aeruginosa. Patients were analyzed for a period of 30 days from time of nosocomial pneumonia onset. Fourteen patients fulfilling the same criteria from a phase IIa studyconducted at the same time/centers were included in the prevalence calculations but not in the clinical outcome analysis.
  
  
  RESULTS
  The prevalence of serotypes was: O6 (29%), O11 (23%), O10 (10%), O2 (9%), and O1 (8%). Serotypes with a prevalence of less than 5% were found in 13% of patients, 8% were classified as not typeable. Across all serotypes, 19% mortality, 70% clinical resolution, 11% clinical continuation, and 5% clinical recurrence were recorded. Age and higher APACHE II (Acute Physiology and Chronic Health Evaluation II) were predictive risk factors associated with probability of death and lower clinical resolution for P. aeruginosa nosocomial pneumonia. Mortality tends to be higher with O1 (40%) and lower with O2 (0%); clinical resolution tends to be better with O2 (82%) compared to other serotypes. Persisting pneumonia with O6 and O11 was, respectively, 8% and 21%; clinical resolution with O6 and O11 was, respectively, 75% and 57%.
  
  
  CONCLUSIONS
  In P. aeruginosa nosocomial pneumonia, the most prevalent serotypes were O6 and O11. Further studies including larger group sizes are needed to correlate clinical outcome with virulence factors of P. aeruginosa in patients with nosocomial pneumonia caused by various serotypes; and to compare O6 and O11, the two serotypes most frequently encountered in critically ill patients.
authors.forename: Qin
authors.initials: Q
authors.lastname: Lu
authors.forename: Philippe
authors.initials: P
authors.lastname: Eggimann
authors.forename: Charles-Edouard
authors.initials: CE
authors.lastname: Luyt
authors.forename: Michel
authors.initials: M
authors.lastname: Wolff
authors.forename: Michael
authors.initials: M
authors.lastname: Tamm
authors.forename: Bruno
authors.initials: B
authors.lastname: François
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Mercier
authors.forename: Jorge
authors.initials: J
authors.lastname: Garbino
authors.forename: Pierre-François
authors.initials: PF
authors.lastname: Laterre
authors.forename: Holger
authors.initials: H
authors.lastname: Koch
authors.forename: Verena
authors.initials: V
authors.lastname: Gafner
authors.forename: Michael P
authors.initials: MP
authors.lastname: Rudolf
authors.forename: Erkan
authors.initials: E
authors.lastname: Mus
authors.forename: Antonio
authors.initials: A
authors.lastname: Perez
authors.forename: Hedvika
authors.initials: H
authors.lastname: Lazar
authors.forename: Jean
authors.initials: J
authors.lastname: Chastre
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Rouby
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003428:Cross Infection / Q000097:blood* / Q000175:diagnosis / Q000401:mortality; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018410:Pneumonia, Bacterial / Q000097:blood* / Q000175:diagnosis / Q000401:mortality; D015995:Prevalence; D011552:Pseudomonas Infections / Q000097:blood* / Q000175:diagnosis / Q000401:mortality; D011550:Pseudomonas aeruginosa / Q000302:isolation & purification*; D012189:Retrospective Studies; D016896:Treatment Outcome