OBJECTIVE To analyze the investigation and handling process of a suspected outbreak of hospital-acquired Serratia marcescens infection in the Neonatal Intensive Care Unit (NICU) of a certain hospital, and to provide valuable reference for the prevention and control of hospital-acquired infections.

METHODS An epidemiological investigation was conducted on three S. marcescens-positive neonates admitted to the NICU of the Affiliated Hospital of Guizhou Medical University from Oct. 12 to 18, 2024. Environmental hygiene sampling was carried out on the surfaces of the ward. The homology of the strains was analyzed, and effective intervention measures were taken.

RESULTS The incidence of S. marcescens sepsis in the NICU from Oct. 12 to 18, 2024 was 2.20% (2/91) compared to 2.35% in the same period of 2023 (2/85), no significant difference was found between the two time periods (P=0.946). Among the three S. marcescens-positive NICU neonates, one was considered community-acquired, while the other two were diagnosed with S. marcescens sepsis. A total of 59 environmental hygiene samples were collected, with one sample detecting S. marcescens in the bedside infusion pump slot of case 1. The homology analysis results showed high homology among the four S. marcescens strains but not completely homologous. After effective preventive and control measures were implemented, suspected S. marcescens clustering events didn′t further occurred.

CONCLUSION The occurrence of this incident may be attributed to inadequate cleaning and disinfection of environmental surfaces and improper hand hygiene practices by some medical staff.