The risk factors and spread of multidrug-resistant Acinetobacter baumannii in intubated patients in a medical intensive care unit

Abstract

Aim: Acinetobacter baumannii is one of the most common causes of ventilator-associated pneumonia in intensive care units. The aim of this study was to determine the risk factors for colonization in the respiratory tract and infection with A. baumannii in a medical intensive care unit (MICU), and to examine the genetic link between strains and the spread of isolates. Materials and methods: This study was conducted prospectively between 1 December 2004 and 31 January 2006 in the MICU. Patients (> 16 years old) admitted to the MICU that were mechanically ventilated and/or intubated were enrolled in the study. Results: Ninety-eight patients were evaluated for A. baumannii colonization during or at the end of their intubation; 44 (45%) of these patients were colonized by A. baumannii. The length of intubation (OR: 1.032, P = 0.014) and diabetes mellitus (OR: 4.140, P = 0.008) were the major risk factors for colonization of the respiratory tract by A. baumannii. During the study period A. baumannii infection developed in 35 (80%) of the 44 colonized patients. The important risk factors for A. baumannii infection were colonization (OR: 3.962, P = 0.006) and tracheostomy (OR: 4.857, P = 0.001). Genotyping analysis was performed for 59 isolates. Overall, 3 clones (clone A, B, and C) were identified in patients; 88% were clone A (52 isolates), 7% were clone B (4 isolates), and 5% were clone C (3 isolates). Conclusion: Length of intubation and diabetes mellitus were significant risk factors for A. baumannii colonization in intubated patients. Moreover, colonization and tracheostomy predisposed patients to infection. Additionally, this study documented the spread of multi-drug resistant A. baumannii in intubated patients in an MICU with limited resources.