ObjectiveTo investigate the risk factors, prognostic factors and prognosis of Multidrug-Resistant Acinetobacter Baumannii (MDR-AB) infection of lower respiratory tract in Intensive Care Unit (ICU) of the Second Affiliated Hospital of Anhui Medical University. MethodsUsing retrospective analysis, we reviewed and compared clinical data of 77 AB infections in lower respiratory tract cases in ICU from January 2013 to March 2015. According to the resistance, patients were divided into a MDR-AB group and a NMDR-AB group. Then the risk factors, prognostic factors and prognosis of MDR-AB infection were analyzed. ResultsA total of 58 cases in the MDR-AB group, 19 cases in the NMDR-AB group were included. The result showed that, the MDR-AB infection in lower respiratory tract could significantly prolong the length of ICU stay (18.5±16.0 vs. 10.6±9.3 days, P<0.05) and increase the mortality (44.8% vs. 11.1%, P<0.01). Logistic regression analysis showed that the independent risk factors for MDR-AB infection in lower respiratory tract included Acute Physiology and Chronic Health Evaluation Ⅱ (Apache Ⅱ) score >15 (OR=0.138, 95%CI 0.03 to 0.625, P=0.01) and use of carbapenems (OR=0.066, 95%CI 0.012 to 0.0346, P=0.001). The independent prognostic factors included placement of drainage tube (OR=8.743, 95%CI 1.528 to 50.018, P=0.015) and use of vasoactive drugs (OR=12.227, 95%CI 2.817 to 53.074, P=0.001). ConclusionThe MDR-AB infection in lower respiratory tract can significantly prolong the length of ICU stay and increase the mortality. The Apache Ⅱ score >15 and use of carbapenems are the risk factors, and the placement of drainage tube and use of vasoactive drugs can increase the mortality of MDR-AB infection of lower respiratory tract in ICU.