ESBL-producing Escherichia coli ST131 versus non-ST131: evolution and risk factors of carriage among French children in the community between 2010 and 2015

The objective of this study was to evaluate the evolution and risk factors of ESBL-producing Enterobacteriaceae (ESBL-E) carriage in children in the community for a long period distinguishing ST131 and non-ST131 Escherichia coli. In this prospective study, rectal samples were obtained from children aged 6-24 months by community paediatricians between 2010 and 2015. Demographic characteristics and risk factors for ESBL-E carriage were collected. Distribution of beta-lactamase genes, phylogenetic groups, ST131 and virulence factors of resistant E. coli was determined. We enrolled 1886 children; 144 (7.6%) harboured ESBL-E, and this rate increased from 4.8% to 10.2% between 2010 and 2015. Risk factors for ESBL-E carriage were being cared for at home [adjusted OR (aOR)=1.8, 95% CI=1.1-2.9], recent antibiotic use (aOR=1.5, 95% CI=1.0-2.1) and travel history (aOR=1.7, 95% CI=1.1-2.6). Among patients carrying ESBL, E. coli (98%) and CTX-M type (90%) predominated and PapGII adhesin, characteristic of pyelonephritogenic E. coli strains, was rare (7%). In 2015, E. coli isolates frequently belonged to the phylogenetic group B2 (48%), and 37% were ST131 compared with 5% in 2010. Compared with non-ESBL-producing strains, ST131 carriage was associated with hospitalization in the last 6 months (aOR=3.5, 95% CI=1.4-8.8). Between 2010 and 2015, the carriage of ESBL-E in community children doubled because of the massive expansion of the E. coli ST131 clonal group. The risk for carrying ST131 was associated with previous hospitalization, but not, contrary to the counterpart, antibiotic treatment, daycare attendance or travel history.