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Abstract

Introduction: Achromobacter species (formerly Alcaligenes) are a rare cause of ventilator-associated pneumonia (VAP). Most cases to date have been in patients with immunocompromised states or chronic comorbidities. No studies of Achromobacter VAP have been published in trauma patients. The purpose of this study is to report the outcomes of critically ill trauma patients with VAP caused by Achromobacter species. Methods: This was a retrospective study of patients admitted to the trauma ICU of the Regional Medical Center at Memphis who had Achromobacter VAP between 1999-2012. Traditional signs and symptoms of VAP triggered a bronchoscopic bronchoalveolar lavage culture. The diagnostic threshold was >100,000 colony forming units/mL. Exclusion criteria were cystic fibrosis, active malignancy, HIV infection or incomplete data. Antibiotic selection and duration of therapy were at the discretion of the trauma team. Clinical and microbiologic success were determined using standard definitions. Results: Twenty eight patients were included (64% male, 37% female). Mean age was 40 years, mean APACHE II score was 29 [8-45] and mean ISS was 40 [16-57]. Unique characteristics compared to a typical VAP population included a long time to diagnosis of VAP (mean 21 days), an extended duration of mechanical ventilation (mean 33 days), a high rate of previous VAP (68%), high incidence of polymicrobial VAP (82%), and long ICU and hospital length of stay (mean 44, 62 days). Monotherapy was utilized in 20 cases (71%). The most commonly used antimicrobial was imipenem (50%). Inadequate empiric antibiotic therapy was common (50%); however, all patients eventually received appropriate treatment. The mean duration of antibiotic therapy was 9 days. The clinical success rate was 89% (25/28), and the microbiologic success rate was 94% (15/16). Of the clinical failures, there was one relapse and two VAP-related deaths. Conclusions: Achromobacter VAP is rare in trauma ICU patients. When it occurs, there is an acceptable clinical and microbiologic success rate.