title: Implications of endotracheal tube biofilm in ventilator-associated pneumonia response: a state of concept.
abstract: BACKGROUND
  Biofilm in endotracheal tubes (ETT) of ventilated patients has been suggested to play a role in the development of ventilator-associated pneumonia (VAP). Our purpose was to analyze the formation of ETT biofilm and its implication in the response and relapse of VAP.
  
  
  METHODS
  We performed a prospective, observational study in a medical intensive care unit. Patients mechanically ventilated for more than 24 hours were consecutively included. We obtained surveillance endotracheal aspirates (ETA) twice weekly and, at extubation, ETTs were processed for microbiological assessment and scanning electron microscopy.
  
  
  RESULTS
  Eighty-seven percent of the patients were colonized based on ETA cultures. Biofilm was found in 95% of the ETTs. In 56% of the cases, the same microorganism grew in ETA and biofilm. In both samples the most frequent bacteria isolated were Acinetobacter baumannii and Pseudomonas aeruginosa. Nineteen percent of the patients developed VAP (N = 14), and etiology was predicted by ETA in 100% of the cases. Despite appropriate antibiotic treatment, bacteria involved in VAP were found in biofilm (50%). In this situation, microbial persistence and impaired response to treatment (treatment failure and relapse) were more frequent (100% vs 29%, P = 0.021; 57% vs 14%, P = 0.133).
  
  
  CONCLUSIONS
  Airway bacterial colonization and biofilm formation on ETTs are early and frequent events in ventilated patients. There is microbiological continuity between airway colonization, biofilm formation and VAP development. Biofilm stands as a pathogenic mechanism for microbial persistence, and impaired response to treatment in VAP.
authors.forename: Sara
authors.initials: S
authors.lastname: Gil-Perotin
authors.forename: Paula
authors.initials: P
authors.lastname: Ramirez
authors.forename: Veronica
authors.initials: V
authors.lastname: Marti
authors.forename: Jose Miguel
authors.initials: JM
authors.lastname: Sahuquillo
authors.forename: Eva
authors.initials: E
authors.lastname: Gonzalez
authors.forename: Isabel
authors.initials: I
authors.lastname: Calleja
authors.forename: Rosario
authors.initials: R
authors.lastname: Menendez
authors.forename: Juan
authors.initials: J
authors.lastname: Bonastre
mesh_terms: D018441:Biofilms / Q000254:growth & development; D004866:Equipment Contamination; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D053717:Pneumonia, Ventilator-Associated / Q000175:diagnosis* / Q000209:etiology*; D011446:Prospective Studies