Abstract
Background:Enterobacter hormaechei, a member of the Enterobacter cloacae complex (ECC), is increasingly recognized as a multidrug-resistant (MDR) nosocomial pathogen. However, subspecies-level genomic data from Ecuador remain limited. Methods: Four clinical E. hormaechei isolates from a hospital in northern Ecuador were analyzed using antimicrobial susceptibility testing and whole-genome sequencing (WGS). Genomic characterization included multilocus sequence typing (MLST), resistome profiling, plasmid replicon detection, integron screening, genomic island analysis, and phylogenetic comparison with publicly available Ecuadorian genomes. Results: WGS identified three isolates as subsp. xiangfangensis (ST136 and ST337) and one as subsp. hoffmannii (ST145). Two ST136 isolates exhibited extensive MDR phenotypes associated with bla(CTX-M-15), bla(OXA-1), bla(ACT-16), and additional aminoglycoside and fluoroquinolone resistance genes. ST145 showed moderate resistance, whereas ST337 remained largely susceptible despite harboring bla(ACT-16). Multiple genomic islands and plasmid replicons (IncF/IncR or IncHI2) were detected. Phylogenetic analysis demonstrated clustering with previously reported Ecuadorian lineages. Conclusions: This study provides subspecies-level genomic characterization of clinical E. hormaechei in Ecuador and describes heterogeneous resistance profiles and associated mobile genetic elements, contributing baseline data for regional surveillance.