Faecal carriage of ESBL-producingEscherichia coliin a remote region of Niger

Abstract

SummaryObjectiveWhole genome sequencing (WGS) of extended-spectrum β-lactamase-producingEscherichia coli(ESBL-E. coli) in developing countries is lacking. Here we describe the population structure and molecular characteristics of ESBL-E. colifaecal isolates in rural Southern Niger.MethodsStools of 383 healthy participants were collected among which 92.4% were ESBL-E. colicarriers; 90 of these ESBL-E. colicontaining stools (109 ESBL-E. coliisolates) were further analysed by WGS, using short- and long-reads.ResultsMost isolates belonged to the commensalism-adapted phylogroup A (83.5%), with high clonal diversity. TheblaCTX-M-15gene was the major ESBL determinant (98.1%), chromosome-integrated in approximately 50% of cases, in multiple integration sites. When plasmid-borne,blaCTX-M-15was found in IncF (57.4%) and IncY plasmids (26.2%). Closely related plasmids were found in different genetic backgrounds. Genomic environment analysis ofblaCTX-M-15in closely related strains argued for mobilisation between plasmids or from plasmid to chromosome.ConclusionsMassive prevalence of community faecal carriage of CTX-M-15-producingE. coliwas observed in a rural region of Niger due to the spread of highly diverse A phylogroup commensalism-adapted clones, with frequent chromosomal integration ofblaCTX-M-15. Plasmid spread was also observed. These data suggest a risk of sustainable implementation of ESBL in community faecal carriage.