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ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Meat Safety and Quality » Research » Publications at this Location » Publication #412294

Research Project: Holistic Tactics to Advance the Microbiological Safety and Quality of the Red Meat Continuum

Location: Meat Safety and Quality

Title: Insights into the plasticity and virulence of Escherichia coli serogroup O45

item KALALAH, ANWAR - University Of Texas At San Antonio
item HIGGINS, ASHLEY - University Of Texas At San Antonio
item KOENIG, SARA - University Of Texas At San Antonio
item Bosilevac, Joseph - Mick
item EPPINGER, MARK - University Of Texas At San Antonio

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/6/2024
Publication Date: 2/29/2024
Citation: Kalalah, A.A., Higgins, A., Koenig, S.S., Bosilevac, J.M., Eppinger, M. 2024. Insights into the plasticity and virulence of Escherichia coli serogroup O45 [abstract]. American Society of Microbiology Microbe. No 5914.

Interpretive Summary:

Technical Abstract: Background: Non-O157 Shiga toxin-producing Escherichia coli of serogroups O26, O45, O103, O111, O121, and O145, collectively known as the 'big six', are major culprits of clinical infections. Among these, the O45 serogroup is responsible for approximately 2% of all reported cases. In this study, we closed the genomes of 22 O45 strains followed by comprehensive phylogenomic and virulence profiling, including publicly available O45 genomes. Material and Methods: Genomes of O45 strains were sequenced to closure on the Illumina and Nanopore platforms. To support lineage-scale analysis, we further included eight publicly available closed genomes of the O45 serogroup featuring diverse H-serotypes and inferred phylogenomic relationships through core-genome multilocus sequence typing (cgMLST). Average nucleotide identities were calculated with FastANI. Closed chromosomes along with recovered plasmids were in silico profiled for unique, shared, and common virulence and resistance inventories. Results and Conclusions: The chromosome sizes range from 4,805,652 to 5,677,709 bp with an average GC-content of 50.73% and an average nucleotide identity of 98.2%. We recorded a total of 6 H-subtypes and 9 sequence types (ST); further two toxin- (stx1a and 2a) and 3 intimin (e, ß, ', and eae-)-suballeles. The shared chromosomal gene inventory was determined at 4,160 genes comprising 2,996 core and 1,164 accessory genes. The established phylogeny revealed a strong correlation between respective H-serotype, ST, and eae-subtype (H2/ST-17/e, H11/ST-29/ß), while the stx profiles are more versatile due to the dynamic acquisition and loss of Stx-prophages. This hybrid-sequencing strategy yielded 73 functionally and phylogenetically diverse plasmids that belong to 19 incompatibility groups. Among these are multidrug-resistant plasmids present in five strains conferring resistance to various antibiotics, including ß-lactams, aminoglycosides, trimethoprim, sulfonamide, and chloramphenicol. This study provides insights into the pathogenome make-up and virulence traits in this emerging human pathogenic lineage.