Clinical characteristics of Acinetobacter baumannii complex bacteremia in patients receiving total parenteral nutrition.

BACKGROUND Acinetobacter baumannii complex (Abc) comprises at least three phenotypically undifferentiated species, including A baumannii, Acinetobacter genomic species 3 (AGS 3) and Acinetobacter genomic species 13TU (AGS 13TU). Abc bacteremia had rarely been described in patients receiving total parenteral nutrition (TPN). In this study, we aimed to determine any differences in the clinical features of patients having TPN and bacteremia due to A baumannii and those due to nonbaumannii Abc (including AGS 3 and AGS 13TU). METHODS The data of patients who had received TPN and had Abc bacteremia in Taipei Veterans General Hospital between August 1998 and December 2007 were retrospectively reviewed. The Acinetobacter isolates were identified to genomic species level. RESULTS A total of 23 patients with A baumannii and 23 patients with nonbaumannii Abc (15 AGS 13TU and 8 AGS 3) bacteremia were identified. The two groups of the patients were comparable regarding their gender, age and APACHE II score at the onset of bacteremia. However, several clinical features were different between the two groups of the patients in the univariate analysis. Furthermore, A baumannii isolates were resistant to more classes of antibiotics than nonbaumannii Abc isolates. The multivariate analysis showed that a higher number of patients with A baumannii bacteremia had received TPN for ≥ 15 days before their onset of bacteremia [odds ratio (OR) 7.214, 95% confidence interval (CI) (1.108-46.989), p = 0.039]. Nevertheless, the 14-day (30.4% vs. 21.7%, p = 0.737) and all-cause in-hospital mortality rate (60.9% vs. 39.1%, p = 0.238) did not differ significantly between these two groups. CONCLUSION The patients with A baumannii bacteremia demonstrated a longer timeframe in the treatment of TPN prior to the onset of bacteremia than those with nonbaumannii Abc bacteremia, however the clinical outcomes between the two groups of the patients did not differ significantly.