Abstract
Enterohaemolysin (Ehx) and alpha-haemolysin are virulence-associated factors (VAFs) causing the haemolytic phenotype in Escherichia coli. It has been shown that chromosomally and plasmid-encoded alpha-haemolysin are characteristic of specific pathotypes, virulence-associated factors and hosts. However, the prevalence of alpha- and enterohaemolysin does not overlap in the majority of pathotypes. Therefore, this study focuses on the characterization of the haemolytic E. coli population associated with multiple pathotypes in human and animal infectious diseases. Using a genomics approach, we investigated characteristic features of the enterohaemolysin-encoding strains to identity factors differentiating enterohaemolysin-positive trom alpha-haemolysin-positive E. coli populations. To shed light on the functionality of Ehx subtypes, we analysed Ehx-coding genes and interred EhxA phylogeny. The two haemolysins are associated with a different repertoire of adhesins, iron acquisition or toxin systems. Alpha-haemolysin is predominantly found in uropathogenic E. coli (UPEC) and predicted to be chromosomally encoded, or nonpathogenic and undetermined E. coli pathotypes and typically predicted to be plasmid-encoded. Enterohae-molysin is mainly associated with Shiga toxin-producing E. coli (STEC) and enterohaemorrhagic E. coli (EHEC) and predicted to be plasmid-encoded. Both types of haemolysin are found in atypical enteropathogenic E. coli (aEPEC). Moreover, we identified a new EhxA subtype present exclusively in genomes with VAFs characteristic of nonpathogenic E. coli. This study reveals a complex relationship between haemolytic E. coli of diverse pathotypes, providing a framework tor understanding the potential role of haemolysin in pathogenesis.
Original language | English |
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Article number | 000999 |
Journal | Microbial Genomics |
Volume | 9 |
Issue number | 4 |
DOIs | |
Publication status | Published - 27 Apr 2023 |
Keywords
- adhesins
- alpha-haemolysin
- EhxA
- enterohaemolysin
- Escherichia coli
- haemolytic
- iron acquisition
- toxin