ObjectiveTo investigate the causes of a suspected outbreak of lower respiratory tract infection (LRTI) caused by carbapenemresistant Acinetobacter baumannii (CRAB) in the general intensive care unit(ICU) of a hospital, and provide scientific evidence for effective control of healthcareassociated infection(HAI).MethodsEpidemiological investigation on patients infected with CRAB and onsite monitoring on ICU environmental hygiene from March 4 to 23,2014 were performed, active prevention and control measures were taken.ResultsA total of 7 patients developed CRAB infection, the total length of stay during epidemic period were 160 days, the infection density of LRTI was 43.75‰（7/160）, 4 of 5 patients at No.02 bed had CRAB LRTI. Univariate analysis revealed that adopting conventional sputum suction procedure was a risk factor; the qualified rate of bacterial count on the object surfaces was 31.75% (20/63). CRAB was also isolated from outer frame of suction device of No.02 bed, which had the same antimicrobial pattern as CRAB from 7 patients’ sputum. After taking a series of controlling measures, there was no CRAB infection case after March 24,2014, this outbreak was effectively controlled.ConclusionThis suspected HAI outbreak may be caused by inadequate disinfection of outer frame of suction device contaminated by CRAB, and horizontally transmitted through manipulation of sputum suction by health care workers. Clean and disinfection of ICU environmental object surfaces is of great importance for preventing HAI.