Abstract: OBJECTIVE To investigate the causes of outbreak of suspected carbapenem-resistant Acinetobacter baumannii (CRAB) infection in intensive care unit (ICU) of a hospital and observe the effects of intervention measures. METHODS The epidemiological survey was conducted for the patients with CRAB infection who were treated in comprehensive ICU of Changzhou Third People's Hospital from Jan. 7, 2024 to Feb. 10, 2024. The samples were collected from the water source-related environments such as hand washing sinks and suction connecting tubes. The staged prevention and control measures were formulated and implemented, and the effects on control of infections were evaluated. RESULTS A total of 5 patients were diagnosed with health care-associated infection with CRAB, 4 of whom had lower respiratory tract infections, and 1 had lower respiratory tract infection complicated with bloodstream infection. All of the 5 CRAB strains were consistent with the drug resistance spectrum (only sensitive to polymyxin). The patients exhibited a clustered distribution in both time and space, primarily concentrated within the same lateral zone of the ICU. Environmental sampling showed that the drug resistance profiles of the CRAB strains that were also detected at sink drains and overflow outlets were consistent with those of the CRAB strains causing the infection. No new cases were identified after the implementation of intensified water source control, standardized sink disinfection, daily replacement of suction tubes, and the use of disposable isolation gowns, and subsequent environmental cultures returned negative. CONCLUSIONS The outbreak of suspected CRAB health care-associated infections in the ICU is jointly caused by local contamination of hand washing sinks and environmental object contamination, the pathogens transmits through the contaminated suction connecting tubes and sputum suction. It is an effective way to intensify the disinfection of hand washing sinks and standardize the management of medica supplies so as to block the transmission.