ObjectiveTo investigate transmission routes of healthcareassociated infection(HAI) caused by methicillinresistant Staphylococcus aureus (MRSA), and make effective measures for preventing and controlling the occurrence and epidemic of HAI caused by multidrugresistance bacteria.MethodsFrom February 24 to March 29,2012, 12 MRSAinfected patients were performed epidemiological study, these patients underwent  bronchoscopy because of tracheal stenosis, strains were identified by amplifying the sequences of 16S rRNA, femA and mecA with  realtime quantitative polymerase chain reaction （PCR）， homology analysis of strains were performed by Spa genotyping. ResultsAll 12 MRSAinfected patients were susceptible to multidrugresistance bacterial infection, 5 cases of MRSA infection  occurred during this hospitalization. Detection of specimens from health care workers and environment were all negative; Spa gene of all 12 MRSA isolates was type t 030,  which was the main epidemic strain in Asia; Spa gene of Staphylococcus aureus isolated from nurses’ noses was type t1425.ConclusionThe assumption of MRSA spread among health care workers aren’t supported by the epidemiological investigation results, genotypes of 12 MRSA isolates are identical, but the result of gene typing can’t be as the evidence of homology of infection ; patients at high risk for MRSA infection should be screened as early as possible, early contact isolation should be performed, so as to prevent and control the occurrence of HAI.