Comparison of the bacterial etiology of early-onset and late-onset ventilator-associated pneumonia in subjects enrolled in 2 large clinical studies

• Published in: Respiratory care Vol. 58; no. 7; p. 1220
• Main Authors: Restrepo, Marcos I, Peterson, Janet, Fernandez, Juan F, Qin, Zhihai, Fisher, Alan C, Nicholson, Susan C
• Format: Journal Article
• Language: English
• Published: United States 01.07.2013
• Subjects: Acinetobacter baumannii - drug effects; Acinetobacter baumannii - isolation & purification; Adult; Age Factors; Aged; Anti-Bacterial Agents - classification; Anti-Bacterial Agents - therapeutic use; APACHE; Bacteremia - drug therapy; Bacteremia - epidemiology; Bacteremia - microbiology; Drug Resistance, Microbial; Female; Humans; Intensive Care Units - statistics & numerical data; Male; Middle Aged; Outcome and Process Assessment (Health Care); Pneumonia, Ventilator-Associated - drug therapy; Pneumonia, Ventilator-Associated - epidemiology; Pneumonia, Ventilator-Associated - microbiology; Prevalence; Pseudomonas aeruginosa - drug effects; Pseudomonas aeruginosa - isolation & purification; Respiration, Artificial - adverse effects; Retrospective Studies; Sex Factors; Staphylococcus aureus - drug effects; Staphylococcus aureus - isolation & purification; Statistics as Topic; Time Factors; mechanical ventilation; early onset; outcome and process assessment; critical care; microbiology; ventilator-associated pneumonia; ICU; late onset
• ISSN: 1943-3654
• DOI: 10.4187/respcare.02173

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. 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. 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. 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.