Complete genome of Escherichia coli sequence type 73 with acquired blaTEM-1 and high genotypic virulence load identified in human saliva

• Published in: Journal of global antimicrobial resistance. Vol. 39; pp. 149 - 152
• Main Authors: McDonagh, Francesca, Tumeo, Anna, Murray, Elaine K., Hallahan, Brian, Miliotis, Georgios
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01-12-2024
• Subjects: blaTEM-1; Escherichia coli; Saliva; ST73; Virulence; blaTEM-1; ST73; Saliva; Escherichia coli; Virulence
• ISSN: 2213-7165; 2213-7173; 2213-7173
• DOI: 10.1016/j.jgar.2024.08.011

Escherichia coli sequence type (ST) 73 is a pandemic lineage of the ExPEC (Extraintestinal Pathogenic E. coli) family associated with conserved virulence. We report the complete genome of a genomically hypervirulent E. coli ST73 strain isolated from the oral cavity of a patient with a diagnosis of treatment resistant schizophrenia and receiving clozapine treatment.
E. coli strain GABEEC132 underwent second and third generation sequencing with Illumina and Oxford-Nanopore-Technologies (ONT) platforms. Antibiotic resistance genes (ARGs) and virulence factors (VFs) were bioinformatically identified using the NCBI-AMR-Finder-Plus database and Virulence-Factors-database (VFDB), respectively. To contextualize the genome within a broader epidemiological framework, phylogenetic analysis was conducted using representative genomes of E. coli ST73 O6:H1 (n = 55).
E. coli strain GABEEC132 was identified as possessing the O6:H1 serotype and classified within the B2 phylogroup. The strain exhibited a high genomic virulence load, encoding for 194 VFs. Additionally, it encoded three ARGs, including an acquired blaTEM-1 located on a rep_cluster_2350 8 237 Kb mobilisable plasmid, presenting phenotypic resistance to ampicillin and piperacillin.
This report provides novel insights into the oral prevalence of genotypically hypervirulent and drug-resistant E. coli ST73, a pandemic lineage.