Abstract: OBJECTIVE To investigate the source and route of transmission of the outbreak of nosocomial infections caused by pan-drug resistance Acinetobacter baumannii（PDRAB）in the neurosurgery care unit（NSICU）,so as to provide basis for the prevention and control of nosocomial infections.METHODS A total of 4specimens from patients′sputum（bronchial aspirates）,healthcare workers’ hands and environment were collected in the early Jan.in2015,and identification and drug susceptibility testing were performed.Gene sequencing analysis technology and phylogenic 16S-23 SrRNA was performed to analyze the gene homology of PDRAB strains.RESULTS The prevalence of PDRAB infection in NSICU was 36.36%（4/11）.The homology of 4PDRAB strains was greater than98% by 16S-23 rRNA gene sequencing analysis.There was one strain of PDRAB detected from the screen of breathing machine by NSICU,whose drug-resistant spectrum was similar to the pathogenic bacteria from 4infected patients,and the homology of them was greater than 98% analyzed by 16S-23 rRNA.CONCLUSION The outbreak of nosocomial infections caused by PDRAB in NSICU is confirmed as a nosocomial infection by homology analysis.We found the source of infection was patient A,and the pathogenic bacteria were through the infectious screen of breathing machine indirect contact transmission.The outbreak has been timely controlled by taking effective control measures actively.