The Clinical Characteristics, Carbapenem Resistance, and Outcome of Acinetobacter Bacteremia According to Genospecies

Background: Few clinical data are available on the relationship between genospecies and outcome of Acinetobacter bacteremia, and the results are inconsistent. We performed this study to evaluate the relationship between genospecies and the outcome of Acinetobacter bacteremia. Methods: Clinical data from 180 patients who had Acinetobacter bacteremia from 2003 to 2010 were reviewed retrospectively. The genospecies were identified by rpoB gene sequence analysis. The clinical features and outcomes of 90 patients with A. baumannii bacteremia were compared to those of 90 patients with non-baumannii Acinetobacter bacteremia (60 with A. nosocomialis, 17 with Acinetobacter species "close to 13 TU'', 11 with A. pittii, and two with A. calcoaceticus). Results: A. baumannii bacteremia was associated with intensive care unit-onset, mechanical ventilation, pneumonia, carbapenem resistance, and higher APACHE II scores, compared to non-baumannii Acinetobacter bacteremia (P<0.05). In univariate analyses, age, pneumonia, multidrug resistance, carbapenem resistance, inappropriate empirical antibiotics, higher APACHE II scores, and A. baumannii genospecies were risk factors for mortality (P<0.05). Multivariate analysis revealed A. baumannii genospecies (OR, 3.60; 95% CI, 1.56-8.33), age, pneumonia, and higher APACHE II scores to be independent risk factors for mortality (P<0.05). Conclusion: A. baumannii genospecies was an independent risk factor for mortality in patients with Acinetobacter bacteremia. Our results emphasize the importance of correct species identification of Acinetobacter blood isolates.