ObjectiveTo evaluate the gene types and drugresistance mechanism of imipenemresistant Acinetobacter baumannii (A. baumannii) causing infection outbreak in an intensive care unit (ICU) . MethodsA. baumannii isolates were identified by API20 NE, antimicrobial susceptibility were detected by disc agar diffusion methods. Three genes including OXA, IMP, and VIM were amplified by polymerase chain reaction (PCR), sequences were analysed using BLAST 2.0. ResultsSeven imipenemresistant A. baumannii isolates all carried OXA23 gene, IMP and VIM genes were not detected.ConclusionThe outbreak was mainly caused by A.baumannii which carried OXA23 gene.