blaNDM-5-encoding ST171 Enterobacter hormaechei: A global genomic and epidemiological perspective.

OBJECTIVE: Six blaNDM-5-positive carbapenem-resistant Enterobacter hormaechei isolates were collected from the emergency intensive care unit of a tertiary hospital in China. This study aimed to conduct a comprehensive genomic and epidemiological analysis of ST171 E. hormaechei harbouring blaNDM-5 on a global scale.

METHODS: Whole-genome sequencing was performed using the Illumina platform, and the genomic characteristics of the isolates were analysed using multiple bioinformatics tools. E. hormaechei strains carrying blaNDM-5 were retrieved from the National Center for Biotechnology Information database. A single nucleotide polymorphism-based phylogenetic tree for ST171 E. hormaechei strains was constructed using Snippy v4.6.0.

RESULTS: Six ST171 E. hormaechei strains carrying blaNDM-5 were isolated from different patients in the EICU over a 9-month period. These strains exhibited resistance to all tested antimicrobial agents except for sulfamethoxazole/trimethoprim and colistin. A total of 12 antimicrobial resistance genes, including blaNDM-5, were identified in these strains. Phylogenetic analysis revealed that all six strains belonged to the same clonal lineage, indicating nosocomial transmission. A comprehensive search of the National Center for Biotechnology Information database identified 75 ST171 E. hormaechei strains carrying blaNDM-5, predominantly of clinical origin, with the highest prevalence in China and the United States. Clonal dissemination was observed both within hospitals and between healthcare facilities in these two countries.

CONCLUSIONS: blaNDM-5-positive ST171 E. hormaechei strains have emerged globally, with significant prevalence in China and the United States. Our study underscores the clonal spread of these strains within hospitals and across healthcare facilities. Continuous surveillance of these strains is crucial for the effective prevention and control of antimicrobial resistance.