Dissemination of ESBL-producing Escherichia coli and carriage in the community worldwide: epidemiology, transmission pathways, molecular insights, and practical aspects

SUMMARY Since the worldwide dissemination of extended-spectrum β-lactamase-producing Escherichia coli (ESBL-Ec) in the early 2000s, ESBL-Ec community carriage has followed divergent epidemiological patterns across regions. Currently, high-income countries (HIC) have a lower prevalence of ESBL-Ec carriage compared to the more concerning prevalence observed in low- and middle-income countries (LMICs). The aim of this review is to summarize the factors that could explain variations in ESBL-Ec prevalence by bridging together information from epidemiological, clinical, and bacterial genetic data. First, geographical differences in ESBL-Ec carriage in the community could be partly related to disparities in socioeconomic levels (e.g., country-level income, Human Development Index) and their associated conditions. Few risk factors associated with ESBL-Ec carriage overlap between LMICs and HICs, except for antibiotic use. Transmission across human, animal, and environmental sectors is much more common in LMICs, whereas inter-human transmission in HICs is more prominent. From the available molecular data, distinct bacterial genetic backgrounds between LMICs (predominantly A and B1 E. coli phylogroups) and HICs (predominantly B2 phylogroup) highlight the clones able to successfully disseminate in these settings. As the dissemination of ESBL-Ec is driven by a complex interplay of socioeconomic, behavioral, and bacterial genetic factors, tailored public health strategies, including antibiotic stewardship and innovative strategies discussed herein, are essential to curb further increases in their prevalence.