ObjectiveTo investigate the causes of an outbreak of healthcareassociated infection with methicillinresistant Staphylococcus aureus(MRSA)  in a neurosurgical intensive care unit(NSICU).  MethodsEpidemiological investigation on 8 patients with lower respiratory tract infection (LRTI) in a NSICU between June 15 and June 28,2104 were performed by combination methods of prospective and retrospective survey.ResultsThe attack rate of MRSA LRTI in NSICU patients was 22.86%, a total of 16 MRSA isolates were detected from patients’ clinical specimens, nasal vestibule, as well as hospital surroundings during the period, pulsedfield gel electrophoresis (PFGE) result revealed that infection outbreak was caused by two subtypes of MRSA; risk factors analysis showed that long length of stay in ICU and aspiration of sputum through bronchoscopy were risk factors for MRSA LRTI.  ConclusionContamination of bronchoscope was the key factor for this  epidemic spread of healthcareassociated MRSA infection.