OBJECTIVE To investigate a suspected hospital-acquired infection cluster of Enterococcus faecium (Efm) in a neonatal intensive care unit (NICU) of the First Medical Center of Chinese PLA General Hospital, identify the source of infection and transmission routes, and provide a reference for precise prevention and control of hospital-acquired infections.

METHODS Epidemiological investigations and environmental microbiological sampling were conducted for two neonates with Efm bloodstream infections in the NICU in Jul. 2024 to detect Efm in the ward environment. Whole-genome average nucleotide identity (ANI) and multilocus sequence typing (MLST) were used to analyze the homology, drug resistance, and virulence factors of Efm isolates from patients and environments. Targeted intervention measures were proposed.

RESULTS Two cases of Efm bloodstream infection were detected. A total of 37 environmental specimens were collected, and 2 were cultured Efm (the wipe dispenser opening and incubator handle of the patients). The drug susceptibility testing results of 2 environmental specimens were consistent with those of the two patient specimens. Genomic analysis confirmed high homology (ANI>99.99%) among the four Efm isolates. After implementing a series of measures including centralized isolation, strict hand hygiene, thorough environmental cleaning and disinfection, strict disinfection and management of invasive devices, enhanced grouping of medical staff for diagnosis and treatment, the incident was effectively controlled.

CONCLUSIONS This incident can be determined as cluster of hospital-acquired infection with Enterococcus faecium in the neonatal intensive care unit. The wet wipes are the source or transmission medium of contamination. Inadequate disinfection of items and the environment, and insufficient hand hygiene of medical staff are the main reasons for this infection outbreak. Early identification of abnormal cluster of infection, investigation of the source of infection and transmission routes and timely implementation of targeted measures are the keys for preventing infection outbreaks.