title: Ventilator-associated pneumonia: role of colonizers and value of routine endotracheal aspirate cultures.
abstract: OBJECTIVE
  To determine the role of colonizers in the causation of ventilator-associated pneumonia (VAP) and the value of routine pre-VAP endotracheal aspirate (EA) cultures in appropriately treating VAP.
  
  
  METHODS
  A prospective observational cohort study was conducted over a period of 15 months. Two hundred patients on mechanical ventilation for>48h were studied.
  
  
  RESULTS
  Acinetobacter spp (33.7%) and Pseudomonas spp (29.8%) were the most common colonizers. Of the 200 patients, 36 developed VAP. In 20 VAP patients, the pre-VAP EA culture-based strategy was not useful. However, in the remaining 16 VAP patients, a pre-VAP EA culture-based strategy would have appropriately treated 13 (81%; 95% confidence interval (CI) 62-100%), in comparison to only nine (56%; 95% CI 32-80%) by the American Thoracic Society (ATS) strategy. The seven patients in whom the ATS guidelines were inappropriate had Acinetobacter spp and Pseudomonas spp resistant to the higher antibiotics recommended by the ATS for multidrug-resistant pathogens. The positive predictive values of Pseudomonas aeruginosa, Acinetobacter baumannii, and methicillin-resistant Staphylococcus aureus (MRSA) isolated from pre-VAP EA cultures were 88%, 83%, and 100%, respectively.
  
  
  CONCLUSIONS
  VAP patients should be treated based on ATS guidelines, but whenever P. aeruginosa, A. baumannii, and MRSA are isolated from pre-VAP EA cultures, the initial antibiotic therapy should be extended to treat these.
authors.affiliation: Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Pondicherry, India. noyaljoseph@yahoo.com
authors.forename: Noyal Mariya
authors.initials: NM
authors.lastname: Joseph
authors.forename: Sujatha
authors.initials: S
authors.lastname: Sistla
authors.forename: Tarun Kumar
authors.initials: TK
authors.lastname: Dutta
authors.forename: Ashok Shankar
authors.initials: AS
authors.lastname: Badhe
authors.forename: Subhash Chandra
authors.initials: SC
authors.lastname: Parija
mesh_terms: D000151:Acinetobacter Infections / Q000188:drug therapy / Q000382:microbiology; D040981:Acinetobacter baumannii / Q000302:isolation & purification; D000328:Adult; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology*; D015331:Cohort Studies; D003470:Culture Media; D005260:Female; D006801:Humans; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000302:isolation & purification; D008875:Middle Aged; D053717:Pneumonia, Ventilator-Associated / Q000175:diagnosis* / Q000188:drug therapy* / Q000453:epidemiology / Q000382:microbiology; D017410:Practice Guidelines as Topic; D011446:Prospective Studies; D011552:Pseudomonas Infections / Q000188:drug therapy / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000302:isolation & purification; D012121:Respiration, Artificial; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000382:microbiology; D014132:Trachea / Q000382:microbiology*
chemical_list: D000900:Anti-Bacterial Agents; D003470:Culture Media