Ventilator-associated pneumonia caused by potentially drug-resistant bacteria

Am J Respir Crit Care Med. 1998 Feb;157(2):531-9. doi: 10.1164/ajrccm.157.2.9705064.


To determine risk factors for ventilator-associated pneumonia (VAP) caused by potentially drug-resistant bacteria such as methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, and/or Stenotrophomonas maltophilia, 135 consecutive episodes of VAP observed in a single ICU over a 25-mo period were prospectively studied. For all patients, VAP was diagnosed based on results of bronchoscopic protected specimen brush (> or = 10(3) cfu/ml) and bronchoalveolar lavage (> or = 10(4) cfu/ml) specimens. Seventy-seven episodes were caused by "potentially resistant" bacteria and 58 episodes were caused by "other" organisms. According to logistic regression analysis, three variables among potential factors remained significant: duration of mechanical ventilation (MV) > or = 7 d (odds ratio [OR] = 6.0), prior antibiotic use (OR = 13.5), and prior use of broad-spectrum drugs (third-generation cephalosporin, fluoroquinolone, and/or imipenem) (OR = 4.1). Distribution of the 245 causative bacteria was analyzed according to four groups defined by prior duration of MV (< 7 or > or = 7 d) and prior use or lack of use (within 15 d) of antibiotics. Although 22 episodes of early-onset VAP in patients receiving no prior antibiotics were caused by antibiotic-susceptible bacteria, 84 episodes of late-onset VAP in patients receiving prior antibiotics were mainly caused by potentially resistant bacteria. Differences in the potential efficacies (ranging from 100% to 11%) against microorganisms of 15 antimicrobial regimens were studied according to classification into these four groups. These findings may provide a more rational basis for selecting the initial therapy of patients suspected of having VAP.

MeSH terms

  • Aged
  • Anti-Bacterial Agents / therapeutic use
  • Bacteria / classification
  • Bacteria / drug effects
  • Bacteria / isolation & purification
  • Bacterial Infections / microbiology*
  • Bacterial Physiological Phenomena*
  • Drug Resistance, Microbial / physiology*
  • Female
  • Humans
  • Intensive Care Units
  • Male
  • Middle Aged
  • Pneumonia / etiology*
  • Pneumonia / microbiology*
  • Prospective Studies
  • Respiration, Artificial / adverse effects*
  • Risk Factors
  • Time Factors


  • Anti-Bacterial Agents