Whole-Genome Sequence Analysis of Shiga Toxin-Producing Escherichia coli Isolated from Livestock Animals in Ghana

TL;DR

This study reports the first genomic analysis of STEC in livestock in Ghana, revealing key serotypes and virulence genes that highlight public health risks.

Contribution

The first whole-genome sequencing study of STEC in Ghana, providing insights into its genomic diversity and zoonotic potential.

Findings

STEC was detected in 12.1% of goat and sheep samples in western Ghana.

Genomic analysis identified STEC serotypes O38:H26, O43:H2, and O157:H7 with distinct virulence gene profiles.

O157:H7 isolates were genetically similar to European clinical and food-derived strains.

Abstract

Shiga toxin-producing Escherichia coli (STEC) is a zoonotic pathogen of public health concern, requiring a One Health approach to clarify its transmission and distribution. However, its prevalence and genomic characteristics in livestock and companion animals remain underexplored in low-income countries. We investigated prevalence and genomic features of STEC in animals in western Ghana, representing the first genomic report of STEC in Ghana. Fecal samples (97) were collected from goats (n = 33), sheep (n = 33), dogs (n = 30), and a cat (n = 1), with STEC detected in 12.1% of goats and sheep samples. Whole-genome sequencing identified serotypes O38:H26, O43:H2, and O157:H7. stx1c and stx2b genes were detected in O38:H26 and O43:H2, whereas stx2c and key virulence genes (chuA, eae, esp, nle, tir, and toxB) were exclusively found in O157:H7. Phylogenetic analysis revealed that O38:H26 isolates form a cluster closely related to clinical strains from the UK. O43:H2 isolates exhibited diverse stx profiles, linking animal, environmental, and clinical strains from North America and the UK. O157:H7 isolates were genetically similar to European clinical and food-derived strains, suggesting that goats and sheep are important STEC reservoirs in Ghana, offering data for public health risk assessment and effective One Health-based control strategies.

Figures