Tracking blaCTX-M transmission through transposable elements in uropathogenic and commensal E. coli

AimTo investigate the nucleotide sequences associated with transposable elements carrying blaCTX-M allelic variants as potential markers for the transmission of antimicrobial resistance genes between domestic animals, humans and the environment.Materials & methodsWe conducted whole-genome sequencing and analyzed the nucleotide sequences of most abundant blaCTX-M allelic variants (blaCTX-M-27, blaCTX-M-55, and blaCTX-M-65) in commensal Escherichia coli (n = 20) from household members in Quito and uropathogenic E. coli (UPEC) (n = 149) isolated from nine clinics in Quito, Ecuador.ResultsThe Ecuadorian commensal E. coli and UPEC displayed identical nucleotide sequences surrounding the blaCTX-M gene and the synteny was similar to those found in other parts of the world; however phylogenetic analysis indicated that the genetic environments in Ecuadorian isolates were unique.ConclusionThese findings suggest that the nucleotide sequences flanking the blaCTX-M genes may be useful for resolving ARG transmission pathways, especially inter-regional analyses.