Risk factors for relapse of ventilator-associated pneumonia related to nonfermenting Gram negative bacilli: A case–control study

SummaryBackgroundThe aim of this study was to determine risk factors for relapse of ventilator-associated pneumonia (VAP) related to nonfermenting Gram negative bacilli (NF-GNB).MethodsThis is a retrospective case–control study based on prospectively collected data. Two hundred and seventy six patients with monobacterial VAP related to NF-GNB were eligible. Patients with subsequent superinfection or persistent pulmonary infection were excluded. Patients with relapse of NF-GNB VAP were matched (1:2) with patients without relapse. Matching criteria included the duration of mechanical ventilation before VAP relapse, age ± 5 years, SAPS II at ICU admission ± 5, and the date of admission. Univariate and multivariate analyses were used to determine risk factors for relapse of NF-GNB VAP in cases and controls.ResultsThirty (10%) patients developed a relapse of NF-GNB VAP, 27 (90%) patients were successfully matched with 54 controls. Inappropriate initial antibiotic treatment was the only variable independently associated with relapse of VAP related to NF-GNB (OR [95% CI] = 8.1 [2–33], p = 0.003). Although ICU-mortality rate was similar in cases and controls (55% vs 72%, p = 0.132), the duration of mechanical ventilation and ICU stay were significantly higher in cases than in controls.ConclusionInappropriate initial antibiotic treatment is independently associated with relapse of VAP related to NF-GNB.