The Epidemiology and Resistance Mechanisms of Acinetobacter baumannii Isolates from the Respiratory Department ICU of a Hospital in China

Abstract

Acinetobacter baumannii is an important nosocomial pathogen able to cause severe infections in an intensive care unit (ICU). However, there is a lack of analysis regarding the epidemiology and resistance of A. baumannii in respiratory department ICUs. In this study, clinical isolates were collected from the respiratory department ICU of Southwest Hospital from January 2009 to December 2010, and the social and demographic information of the patients from whom the isolates were taken was obtained from the Southwest Hospital information system. The minimal inhibitory concentration (MIC) of the isolates was determined by the agar dilution method. The carbapenemase-encoding resistance genes of these isolates were amplified using PCR. The clonal relationship of isolates was analyzed by pulsed-field gel electrophoresis (PFGE). Forty-six isolates were collected from the respiratory department ICU, and the antibiotics minocycline and quinolone had higher drug sensitivity against these isolates. The OXA-51, OXA-23, and IMP-4 genes were present at rates of 100% (46/46), 67.4% (31/46), and 41.3% (19/46), respectively. Forty-six isolates had 12 different PFGE genotypes. The results above suggested that the hospital environment and patients contributed to nosocomial infections, and the spread of resistance genes in the hospital was common.