Carriage of extended-spectrum β-lactamase–producing Enterobacterales among healthy adults: a cohort study in Finland

This is the authors' abstract. We don't add key points for this paper.

Background Despite increasing antimicrobial resistance (AMR) in clinical samples in high-income countries (HICs), data on healthy community dwellers remains limited. We explored the prevalence and types of extended-spectrum β-lactamase-producing Enterobacterales (ESBL-PE) in a HIC , Finland, comparing our findings to community and bloodstream infection (BSI) isolates reported in the literature. Methods We recruited healthy Finnish adults (18–65 years) with no travel history to low- and middle-income countries (LMIC) over the past year to participate in a clinical vaccine trial, OEV-123. All participants completed questionnaires, and for this AMR- related part, we assessed their background stool samples for ESBL-PE, carbapenemase-producing Enterobacterales (CPE), and OXA-48-producing CPE. Risk factor analyses were conducted. Whole-genome sequencing (WGS) was performed in isolates to assess sequence types (ST), co-resistance, and virulence factors. Results Among 738 volunteers, 33 (4.5%) were colonised with ESBL-PE, all identified as Escherichia coli. Previous residence in a low- and middle-income country (LMIC) was identified as a risk factor. No CPE or CPE/OXA-48 strains were detected. The most common STs were ST131 and ST38. Compared to ESBL-PE isolates from Norwegian BSI data, our community samples had a lower prevalence of ST131 (13.8% versus 58.8% in 2017). WGS revealed high antimicrobial resistance gene (ARG) frequencies against quinolones (82.8%) and aminoglycosides (69.0%). Virulence gene/pathotype analysis identified 44.8% of the ESBL- E. coli as extraintestinal pathogenic E. coli (ExPEC), 55.2% as uropathogenic E. coli (UPEC), and 10.3% as diarrhoeagenic E. coli (DEC). Conclusions We estimated a background prevalence of 4.5% for ESBL-PE among individuals aged 18–65 years in Finland. The combination of low prevalence and high ST diversity suggests low transmission rates and no endemically circulating clones.