title: Differing pathways of lower airway colonization and infection according to mode of ventilation (endotracheal vs tracheotomy).
abstract: OBJECTIVE
  To determine whether the pathogenesis of lower airway colonization and infection was endogenous (via the oropharynx) or exogenous (via the endotracheal tube or tracheotomy) during the 2 modes of ventilation in the same subset of children requiring long-term ventilation.
  
  
  METHODS
  Prospective, observational cohort study.
  
  
  METHODS
  A pediatric intensive care unit and a respiratory ward.
  
  
  METHODS
  Consecutive admissions between September 1, 1993, and August 30, 1998.
  
  
  RESULTS
  Cultures were obtained simultaneously from the oropharynx and tracheobronchial tree on admission to the pediatric intensive care unit, at placement of the tracheotomy, and afterward twice weekly. Forty-five patients were studied. Lower airways were always sterile in 6 children, 39 children (87%) developed a total of 82 episodes of colonization, and 17 (38%) progressed to 25 episodes of infection. The number of infected children was halved once they had a tracheotomy (7 children [16%]). Of the 107 episodes of colonization and infection, 41 and 66 occurred during endotracheal ventilation and via a tracheotomy, respectively. Primary endogenous episodes of colonization and infection due to bacteria present in the admission flora in the pediatric intensive care unit were significantly more common with endotracheal ventilation than during ventilation via a tracheotomy (31/41 [76%] vs 36/66 [55%]; P =.03). Secondary endogenous and exogenous episodes of colonization and infection due to bacteria associated with the respiratory ward were significantly more frequent when ventilation was continued through a tracheotomy than during endotracheal ventilation (30/66 [45%] vs 10/41 [24%]; P =.02).
  
  
  CONCLUSIONS
  Surveillance samples allow the distinction between primary endogenous ("imported" bacteria) from secondary endogenous and exogenous ("nosocomial" microorganisms) colonization and infection. This classification permits the development of preventive strategies to control both endogenous and exogenous pathways.
authors.affiliation: Department of Otorhinolaryngology, Royal Liverpool Children's NHS Trust of Alder Hey, Liverpool, England. paddy@morarp.freeserve.co.uk
authors.forename: Pradeep
authors.initials: P
authors.lastname: Morar
authors.forename: Vivian
authors.initials: V
authors.lastname: Singh
authors.forename: Zvoru
authors.initials: Z
authors.lastname: Makura
authors.forename: Andrew
authors.initials: A
authors.lastname: Jones
authors.forename: Paul
authors.initials: P
authors.lastname: Baines
authors.forename: Andrew
authors.initials: A
authors.lastname: Selby
authors.forename: Richard
authors.initials: R
authors.lastname: Sarginson
authors.forename: Julie
authors.initials: J
authors.lastname: Hughes
authors.forename: Rick
authors.initials: R
authors.lastname: van Saene
mesh_terms: D000293:Adolescent; D001980:Bronchi / Q000382:microbiology / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D015169:Colony Count, Microbial; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007442:Intubation, Intratracheal / Q000009:adverse effects*; D008297:Male; D009960:Oropharynx / Q000382:microbiology / Q000503:physiopathology; D011446:Prospective Studies; D012121:Respiration, Artificial / Q000009:adverse effects*; D012137:Respiratory System / Q000382:microbiology* / Q000503:physiopathology*; D012141:Respiratory Tract Infections / Q000209:etiology* / Q000382:microbiology / Q000503:physiopathology*; D014132:Trachea / Q000382:microbiology / Q000503:physiopathology; D014140:Tracheotomy / Q000009:adverse effects*