Journal: Frontiers in Microbiology

Article Title: Clonal and plasmid-mediated dissemination of CTX-M-14–producing Escherichia coli within a single cattle farm in Japan

doi: 10.3389/fmicb.2026.1772995

Figure Lengend Snippet: Summary of genomic features, resistance determinants, and conjugation profiles of CTX-M-14–producing Escherichia coli.

Article Snippet: Antimicrobial susceptibility of the isolates was determined through agar microdilution according to the Clinical & Laboratory Standards Institute guidelines, and quality control was performed using the reference strain E. coli ATCC 25922 ( ).

Techniques: Conjugation Assay, Sequencing, Plasmid Preparation

Journal: Frontiers in Microbiology

Article Title: Clonal and plasmid-mediated dissemination of CTX-M-14–producing Escherichia coli within a single cattle farm in Japan

doi: 10.3389/fmicb.2026.1772995

Figure Lengend Snippet: Core-genome SNP-based phylogenetic tree showing the isolation source, sequence types, mutations in QRDR, and plasmid contents of E. coli from parent cattle, calves, and a farmer. The tree was constructed based on core-genome SNPs using the General Time Reversible (GTR) model with 1,000 bootstrap replicates. The accompanying metadata matrix displays relevant genomic and phenotypic attributes for each isolate. The two E. coli isolates belonging to ST533 (from the parent cattle and calf 1), which showed clonal identity (one SNP difference and identical cgST), are highlighted with a yellow background to emphasize their close genetic relatedness. SNP, single-nucleotide polymorphism; QRDR, quinolone resistance–determining region; ST, sequence type; cgST, core genome ST.

Article Snippet: Antimicrobial susceptibility of the isolates was determined through agar microdilution according to the Clinical & Laboratory Standards Institute guidelines, and quality control was performed using the reference strain E. coli ATCC 25922 ( ).

Techniques: Isolation, Sequencing, Plasmid Preparation, Construct

Journal: Frontiers in Microbiology

Article Title: Clonal and plasmid-mediated dissemination of CTX-M-14–producing Escherichia coli within a single cattle farm in Japan

doi: 10.3389/fmicb.2026.1772995

Figure Lengend Snippet: Summary of clonal and plasmid-mediated dissemination of bla CTX-M-14– positive E. coli on a cattle farm. Schematic summary of genomic relationships among bla CTX-M-14 –positive E. coli isolates from cattle and a farmer in 2013. Core-genome SNP analysis identified a clonally identical ST533 pair from a parent cattle and its calf (0–1 SNP difference), consistent with recent clonal transmission. In contrast, distinct E. coli lineages harbored highly conserved IncI1 bla CTX-M-14 –encoding plasmids (>99.9% sequence identity), suggesting dissemination of closely related plasmids across hosts and bacterial backgrounds. High conjugative transferability supports the potential role of these plasmids in ESBL spread at the livestock–human interface.

Article Snippet: Antimicrobial susceptibility of the isolates was determined through agar microdilution according to the Clinical & Laboratory Standards Institute guidelines, and quality control was performed using the reference strain E. coli ATCC 25922 ( ).

Techniques: Plasmid Preparation, Transmission Assay, Sequencing