[Analysis of risk factors on prognosis of Acinetobacter baumannii bloodstream infection]

To explore the risk factors on prognosis of Acinetobacter baumannii bloodstream infection.

Clinical data from 78 patients with Acinetobacter baumannii bloodstream infection hospitalized in First Affiliated Hospital of Nanjing Medical University from January 2010 to November 2012 were analyzed retrospectively. According to the 28-day prognosis after admission, the patients were divided into non-survivors (n=40) and survivors (n=38). Data on demographic and clinical characteristics, wards, underlying diseases, treatments, invasive medical procedures, bacterial resistance to antibiotics, and acute physiology and chronic health evaluation II (APACHEII) score in the beginning were collected. The index as an independent risk factor of mortality was demonstrated by multivariate logistic regression analysis. The predictor value was concluded by comparing area under the receiver operating characteristic curve (ROC curve) of each index.

Risk factors of mortality of Acinetobacter baumannii bloodstream infection goes as following, including intensive care unit admission[ICU, odds ratio (OR)=12.9,95% confidence interval (95%CI) 2.4-63.5, P=0.001], trachea intubation or tracheostomy (OR=6.2, 95%CI 1.5-30.4, P=0.023), invasive mechanical ventilation (OR=5.1, 95%CI 1.4-22.6, P=0.042), invasive medical procedure besides central venous catheter (including thoracentesis, bone marrow puncture, lumbar puncture, catheterization, bronchoalveolar lavage with bronchofibroscope, arteriovenous fistula plastic operation, OR=8.4, 95%CI 1.7-37.8, P=0.011), APACHEII score ≥19 in the beginning (OR=35.4, 95%CI 3.8-318.6, P=0.001). With respect to APACHE II score≥ 19 as mortality cut-off point, an area under the receiver operating curve of 0.938 was statistically significant (P<0.05), with sensitivity 76.2% and specificity 94.1%. The relationship between prognosis and antibiotic resistance did not have statistically significance.

Invasive medical procedures and treatments were associated with increased mortality of patients with Acinetobacter baumannii bloodstream infection. A strong predictor of adverse outcome in such conditions was APACHEII score ≥19.