Genomic Characterization of a Uropathogenic Escherichia coli ST405 Isolate Harboring blaCTX-M-15-Encoding IncFIA-FIB Plasmid, blaCTX-M-24-Encoding IncI1 Plasmid, and Phage-Like Plasmid

Escherichia coli sequence type 405 is an emerging antibiotic-resistant clonal group associated with the global dissemination of extended-spectrum beta-lactamase-producing E. coli. In this study, we report the genome assembly and characterization of a uropathogenic E. coli ST405 strain, SZESBLEC201, based on long and short reads obtained from the Nanopore and Illumina sequencing platforms, respectively. Whole-genome sequencing revealed that SZESBLEC201 harbors a 5,020,403 bp chromosome and three plasmids, namely, pSZESBLEC201-1, pSZESBLEC201-2, and pSZESBLEC201-3. pSZESBLEC201-1 (111,621 bp) belongs to the IncFIA-FIB type and harbors bla(CTX-M-15). However, this plasmid does not harbor conjugative transfer-associated genes, rendering pSZESBLEC201-1 unable to be conjugatively transferred. pSZESBLEC201-2 (95,138 bp) is a phage-like plasmid that shows a strong genome synteny with Escherichia phage P1 but with the absence of mobile genetic elements and some regulatory genes. pSZESBLEC201-3 (92,865 bp) belongs to the IncI1 type and carries bla(CTX-M-24). In contrast to pSZESBLEC201-1, pSZESBLEC201-3 retains its full active conjugation machinery and can be transferred via conjugation. The genetic features of the genome show that the SZESBLEC201 has a unique virulence pattern compared with genetically similar strains found in the same country (China). The plasmid backbones exhibit a high degree of similarity to those of geographically distant isolates, highlighting the global spread of bla(CTX-M) genes and the genome plasticity of this clonal group. The coexistence of two bla(CTX-M) variants in the same strain increases the risk of the emergence of new bla(CTX-M) variants. Further studies on phage-like plasmids are necessary to provide insights into their biological activities and clinical significance.

Automated summary

In this study, the genome assembly and characterization of a uropathogenic E. coli ST405 strain, SZESBLEC201, were reported. The strain carries three plasmids, with two of them harboring antibiotic resistance genes. Only one plasmid can be transferred via conjugation. The unique virulence pattern of SZESBLEC201 compared to genetically similar strains and the global spread of antibiotic resistance genes were highlighted.