Risk Factors and Clinical Outcomes of Pan-drug Resistant Acinetobacter baumannii Bacteremia

  Objective  To determine the risk factors and outcomes of pan-drug resistant Acinetobacter baumannii(PDRAB) bacteremia by comparing clinical data of PDRAB patients with those of non-pan-drug resistant Acinetobacter baumannii (NPDRAB) bacteremia.

  Methods  This retrospective cohort study included patients with Acinetobacter baumannii bacteremia diagnosed and treated in Peking Union Medical College Hospital during January 1, 2010 and December 31, 2012. Clinical data and laboratory test results of the patients were collected with unified forms. The primary clinical outcome was in-hospital death within 14 days after sample collection for blood culture of Acinetobacter baumannii.

  Results  A total of 52 patients with Acinetobacter baumannii bacteremia were included, with the mean age of 54±20 years and including 30 (57.7%) males. The mean acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) score and sepsis-related organ failure assessment (SOFA) score were 21±9 and 10±5, respectively. The median length of hospital stay before Acinetobacter baumannii bacteremia was 12 days (7-20 days). Among these patients, only 6 cases were sensitive to carbapenem. Thirty-three cases were infected by NPDRAB and 19 by PDRAB. Compared with NPDRAB patients, PDRAB patients had a higher rate of receiving mechanical ventilation (94.7% vs. 63.6%, P=0.031) and a longer hospital stay (median:17 days vs. 10 days, P=0.025) before Acinetobacter baumannii infection. The 14-day mortality rate in patients with Acinetobacter baumannii bacteremia was 67.3% (35/52). In multivariate analysis, septic acute kidney injuryodds ratio (OR) 7.9, 95% confidence interval (CI) 1.113-55.448, P=0.039, inappropriate anti-microbial therapy (OR 9.4, 95% CI 1.020-87.334, P=0.048), and procalcitonin level (OR 1.3, 95% CI 1.332-1.088, P=0.005) were independent risk factors of 14-day mortality in Acinetobacter baumannii bacteremia patients.

  Conclusions  Acinetobacter baumannii has multi-drug resistance and is even not susceptible to all currently available systemic antimicrobials. Acinetobacter baumannii infection is associated with high mortality rate. Mechanical ventilation and long hospital stay before occurrence of bacteremia are risk factors for PDRAB bacteremia. However, PDRAB infection itself is not a predictor of poor prognosis. Inappropriate antimicrobial therapy, septic acute kidney injury, and procalcitonin level are independent risk factors of 14-day mortality in Acinetobacter baumannii bacteremia.