Antimicrobial resistance and genomic characteristics of multidrug resistant diarrheagenic Escherichia coli from human and food samples in Henan Province
This study was aimed at investigating the antimicrobial susceptibility and genomic characteristics of multidrug resistant diarrheagenic Escherichia coli isolated from human and food samples in Henan Province from 2017 to 2022.A total of 101 strains of multidrug resistant diarrheagenic E.coli were subjected to antimicrobial susceptibility testing with the broth di-lution method.Whole genome sequencing was performed to analyze the antimicrobial resistance genes,multilocus sequence typ-ing,and plasmid types.The sequencing data were used to construct a phylogenetic tree based on core genome single-nucleotide polymorphisms(cgSNPs).The isolates showed the highest resistance to ampicillin(87.1%),followed by tetracycline(79.2%)and nalidixic acid(64.4%).The resistance rate to cefotaxime was 38.6%.All 101 strains were classified into 60 STs,among which ST10,ST1491,and ST38 were dominant.Moreover,23 distinct plasmid replicons were identified,among which IncFIB was dominant.Diverse antimicrobial resistance genes(including quinolone,aminoglycoside,β-lactamase,and tetracycline)were identified.Insertion sequences(IS26,IS903B,and ISECP 1)were identified in upstream and downstream analysis of the gene context of the extended-spectrum β-lactamase bla CTX-M-14 and bla CTX-M-55 genes.In conclusion,multidrug resistant diarrhea-genic Escherichia coli isolated from clinical and food samples in Henan Province showed high genetic diversity and high antimi-crobial resistance.The dissemination of blaCTX-M carried by the strains was shown to be associated with the insertion sequence(IS).