Incidence and outcome of healthcare-associated Acinetobacter baumannii in chronically ventilated patients in a tertiary care hospital in Taiwan

Introduction Most studies related to healthcare-associated infection with Acinetobacter baumannii (HAIA) are on acutely ventilated patients. Little is known regarding the incidence and outcomes of HAIA in chronically ventilated patients. Methods A retrospective study of chronically ventilated patients covering the period May 2002 to May 2008 was conducted to determine the incidence of patients with HAIA. The Cox proportional hazard model was used to estimate differences in the 30-day mortality between those with and those without HAIA by case-control study after controlling for confounders. Results Of 240 patients who were chronically ventilated for 49,207 days, 78 (32.5%) acquired HAIA at a rate of 1.59/1,000 patient day. The central venous catheter-related bloodstream infections rate was 8.78 per 1,000 catheter days; the ventilator-associated pneumonia rate was 1.26 per 1,000 ventilator days; and the catheter-associated urinary tract infections rate was 0.17 per 1,000 catheter days. Fifty (64.1%) HAIA and 58 (64.4%) non-HAIA patients were treated well and survived without ICU admission. After univariate and multivariate analyses, prolonged ventilation days (odds ratio: 3.4; 95% confidence interval: 1.7-6.1; P = 0.01] and inappropriate empiric antibiotics within 48 hours (odds ratio: 7.9; 95% confidence interval: 3.9-9.8; P = 0.02) were independent factors that predicted the 30-day mortality of HAIA among chronically ventilated patients. Conclusions Although chronically ventilated patients with HAIA have longer ventilator days, higher antibiotics resistance, and high rate per 100 patients of ventilator-associated pneumonia, most patients are treated well. Compared with patients without HAIA, prolonged ventilation days and inappropriate empiric antibiotics within 48 hours are independent factors of the 30-day mortality.