Prevalence of Genotypic Antimicrobial Resistance in Clinical Shiga Toxin-Producing Escherichia coli in Norway, 2018 to 2020. AMR-STEC

Shiga toxin-producing Escherichia coli (STEC) can cause severe to fatal disease in humans. Antimicrobial treatment is sometimes necessary, but contraindicated due to undesirable clinical outcome. However, recent studies have shown promising outcomes following antimicrobial treatment. Before the establishment of a possible antimicrobial treatment strategy for STEC infections, the prevalence of antimicrobial resistance in STEC needs to be determined. Aim: We aim to characterise genotypic antimicrobial resistance determinants in clinical STEC in Norway, and determine the prevalence of genotypic resistance in order to inform possible antimicrobial treatment options for STEC infections.Methodology: We included all clinical STEC submitted to the Norwegian Reference Laboratory from March 2018 to April 2020. All samples were whole genome sequenced and screened for genotypic antimicrobial resistance and virulence determinants, and plasmid incompatibility groups. We performed phylogenetic clustering of STEC by core genome multi-locus sequence typing, and statistical association analyses between isolate characteristics and genotypic resistance.