title: Impact of piperacillin resistance on the outcome of Pseudomonas ventilator-associated pneumonia.
abstract: BACKGROUND
  The impact of antibiotic resistance on the outcome of infections due to Gram-negative bacilli, especially Pseudomonas, remains highly controversial. STUDY OBJECTIVE, DESIGN, AND PATIENTS: We evaluated the impact of piperacillin resistance on the outcomes of Pseudomonas aeruginosa ventilator-associated pneumonia (VAP) for patients who had received appropriate empiric antibiotics before enrollment in the PNEUMA trial, a multicenter randomized study comparing 8 vs 15 days of antibiotics.
  
  
  RESULTS
  Despite similar characteristics at intensive care unit (ICU) admission, patients infected with piperacillin-resistant Pseudomonas strains were more acutely ill at VAP onset and had a higher 28-day mortality rate (37 vs 19%; P = 0.04) than those with piperacillin-susceptible Pseudomonas VAP. Factors associated with 28-day mortality retained by multivariable analysis were: age (OR: 1.07; 95% CI: 1.03-1.12); female gender (OR: 4.00; 95% CI: 1.41-11.11); severe underlying comorbidities (OR: 2.73; 95% CI: 1.02-7.33); and SOFA score (OR: 1.17; 95% CI: 1.03-1.32), but piperacillin resistance did not reach statistical significance (OR: 2.00; 95% CI: 0.72-5.61). The VAP recurrence rates, either superinfection or relapse, and durations of mechanical ventilation and ICU stay did not differ as a function of Pseudomonas-resistance status.
  
  
  CONCLUSIONS
  For patients with Pseudomonas VAP benefiting from appropriate empiric antibiotics, piperacillin resistance was associated with increased disease severity at VAP onset and higher 28-day crude mortality; however, after controlling for confounders, piperacillin-resistance was no longer significantly associated with 28-day mortality. The VAP recurrence rates and durations of ICU stay and mechanical ventilation did not differ for susceptible and resistant strains.
authors.affiliation: Groupe Hospitalier Pitié-Salpêtrière, Assistance Publique, Hôpitaux de Paris Université Pierre et Marie Curie, Paris 6, Service de Réanimation Médicale, Institut de Cardiologie, Paris, France, alain.combes@psl.aphp.fr
authors.forename: Alain
authors.initials: A
authors.lastname: Combes
authors.forename: Charles-Edouard
authors.initials: CE
authors.lastname: Luyt
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Fagon
authors.forename: Michel
authors.initials: M
authors.lastname: Wolff
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Trouillet
authors.forename: Jean
authors.initials: J
authors.lastname: Chastre
mesh_terms: D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D001999:Bronchoscopy; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D010878:Piperacillin / Q000627:therapeutic use*; D053717:Pneumonia, Ventilator-Associated / Q000188:drug therapy* / Q000382:microbiology / Q000401:mortality; D011552:Pseudomonas Infections / Q000188:drug therapy* / Q000401:mortality / Q000503:physiopathology; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000472:pathogenicity; D012720:Severity of Illness Index
chemical_list: D000900:Anti-Bacterial Agents; D010878:Piperacillin