Emergence of blaOXA-244 in a single and dual-carbapenemase-producing clinical isolates of Escherichia coli from the United Arab Emirates.

ObjectivesCarbapenem-resistant Enterobacterales have emerged as a major global health concern owing to their rapid dissemination and limited therapeutic options. Here we report the first detection of blaOXA-244 in Escherichia coli from the United Arab Emirates (UAE) and characterize two isolates genotypically and phenotypically, comparing them with geographically diverse public strains sharing the same sequence type (ST).MethodsThe isolates were recovered from the urine of a patient with metastatic cancer and from the abdominal fluid of a patient with sepsis. Antimicrobial susceptibility testing, including newer β-lactam and β-lactam/β-lactamase-inhibitors (BL/BLIs), and whole-genome sequencing were performed. Comparative genomic analysis was conducted against global and a defined Middle Eastern/North African subset matched by ST and carbapenemase profile.ResultsThe two isolates were genetically distinct: one carried blaOXA-244 alone and belonged to ST131, whereas the other harboured dual carbapenemases (blaOXA-244 and blaNDM-5) and belonged to ST361. Chromosomal location of blaOXA-244 was confirmed by Southern hybridization. Both isolates were multidrug-resistant, enriched with resistance genes spanning multiple antibiotic classes and virulence genes that support their pathogenicity. Phenotypically, the ST131 isolate remained susceptible to ceftazidime/avibactam and several BL/BLIs combinations, whereas the NDM-5-carrying ST361 isolate was resistant to ceftazidime/avibactam, cefepime/enmetazobactam, and cefepime/taniborbactam, highlighting the therapeutic challenge posed by metallo-β-lactamase co-production. Notably, both isolates remained susceptible to cefepime/zidebactam, cefiderocol, tigecycline, and colistin, and both showed low MICs for meropenem/xeruborbactam. The phylogenetic placement of both UAE isolates is consistent with membership in distinct carbapenem-resistant lineages detected across multiple countries; however, the routes of acquisition could not be inferred.ConclusionsThis is the first report of blaOXA-244 in E. coli from the UAE with two unrelated high-risk backgrounds. A dual OXA-244/NDM-5 ST361 lineage disseminated regionally since 2019 was identified. Because OXA-244 evades routine detection, genomic surveillance is needed to detect such emerging variants and to inform appropriate antimicrobial therapy.