Increase of Widespread A, B1 and D Escherichia Coli Clones Producing a High Diversity of CTX-M-Types in a Portuguese Hospital

AIM: To characterize temporal shifts in extended-spectrum β-lactamases (ESBLs) and clones of clinical Escherichia coli isolates. MATERIALS & METHODS: All ESBL-producing E. coli isolates from a Portuguese hospital (n = 112; June 2006-June 2007 and January-December 2010) were characterized by identification of phylogenetic groups, ESBL-types and virulence genes, XbaI-PFGE and MLST. RESULTS: We observed a substantial increase in widespread E. coli clones from phylogroups A, B1 and D (e.g., ST10, ST23, ST117, ST155, ST648) producing mainly CTX-M-1, -14, -32 or SHV-12, along with a decrease in the proportion of the predominant CTX-M-15-producing B2-ST131 clone. CONCLUSION: The amplification of diverse CTX-M-producing A, B1 and D clonal complexes, which have been long identified in Portuguese nonclinical settings, unveils a role for these reservoirs in the landscape of ESBL-producing E. coli in the clinical setting.