Molecular characteristics of extended-spectrum β-lactamase-producing Escherichia coli from Rio de Janeiro, Brazil

Twenty-five extended-spectrum β-lactamase (ESBL)-producing Escherichia coli clinical isolates from Rio de Janeiro, Brazil were characterized by isoelectric focusing, PCR and sequencing of blaESBL genes, plasmid-mediated quinolone resistance determinants, phylogenetic groups, replicon typing, pulsed-field electrophoresis, and multilocus sequencing typing. Twenty-three (92%) ESBL-producing E. coli isolates were positive for blaCTX-M genes, aac(6′)-Ib-cr, and qnrB. Genetic relatedness of ESBL producers clustered seven (28%) CTX-M-15-producing isolates as sequence type (ST)410, clonal complex (CC) 23, and two (8%) as clone O25-ST131. Our results illustrate the predominance of phylogroup A (52%), ST410 (CC 23) and CTX-M-15 among ESBL-producing E. coli isolates from hospitals in Rio de Janeiro.