title: Comparison of the bacterial etiology of early-onset and late-onset ventilator-associated pneumonia in subjects enrolled in 2 large clinical studies.
abstract: BACKGROUND
  Ventilator-associated pneumonia (VAP) is classified as early-onset or late-onset, in part, to identify subjects at risk for infection with resistant pathogens. We assessed differences in the bacterial etiology of early-onset versus late-onset VAP.
  
  
  METHODS
  Subjects enrolled in 2004-2006 in 2 clinical studies of doripenem versus imipenem or piperacillin/tazobactam, with a diagnosis of VAP (n = 500) were included in the analysis. Subjects were classified by ventilator status: early-onset VAP (< 5 d of ventilation) or late-onset VAP (≥ 5 d of ventilation). Baseline demographics and bacterial etiology were analyzed by VAP status.
  
  
  RESULTS
  Late-onset VAP subjects had higher Acute Physiology and Chronic Health Evaluation (APACHE II) scores (mean 16.6 versus 15.5, P = .008). There were no significant differences in Clinical Pulmonary Infection Score, sex, age, or presence of bacteremia between the groups. A total of 496 subjects had a baseline pathogen, and 50% of subjects in each group had ≥ 2 pathogens. With the exception of Staphylococcus aureus, which was common in early-onset VAP, the pathogens (including potentially multidrug-resistant (MDR) pathogens) isolated from early-onset versus late-onset VAP were not significantly different between groups. Acinetobacter baumannii or Pseudomonas aeruginosa with decreased susceptibility to any study drug was observed in early-onset and late-onset VAP subjects.
  
  
  CONCLUSIONS
  There were no significant differences in the prevalence of potential MDR pathogens associated with early-onset or late-onset VAP, even in subjects with prior antibiotics. Empiric therapy for early-onset VAP should also include agents likely to be effective for potential MDR pathogens. Further prospective studies should evaluate microbiology trends in subjects with VAP.
authors: Division of Pulmonary and Critical Care, University of Texas Health Science Center at San Antonio, TX 77030, USA. restrepom@uthscsa.edu
authors: Marcos I
authors: MI
authors: Restrepo
authors: Janet
authors: J
authors: Peterson
authors: Juan F
authors: JF
authors: Fernandez
authors: Zhihai
authors: Z
authors: Qin
authors: Alan C
authors: AC
authors: Fisher
authors: Susan C
authors: SC
authors: Nicholson
mesh_terms: D018806:APACHE; D040981:Acinetobacter baumannii / Q000187:drug effects / Q000302:isolation & purification; D000328:Adult; D000367:Age Factors; D000368:Aged; D000900:Anti-Bacterial Agents / Q000145:classification / Q000627:therapeutic use; D016470:Bacteremia / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology; D004352:Drug Resistance, Microbial; D005260:Female; D006801:Humans; D007362:Intensive Care Units / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D010043:Outcome and Process Assessment, Health Care; D053717:Pneumonia, Ventilator-Associated / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology; D015995:Prevalence; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000302:isolation & purification; D012121:Respiration, Artificial / Q000009:adverse effects*; D012189:Retrospective Studies; D012737:Sex Factors; D013211:Staphylococcus aureus / Q000187:drug effects / Q000302:isolation & purification; D013223:Statistics as Topic; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents
keywords: ICU; critical care; early onset; late onset; mechanical ventilation; microbiology; outcome and process assessment; ventilator-associated pneumonia