Decoding E. coli O157:H7: Insights from DNA Sequencing and Phylogenetic Analysis for Enhanced Public Health Strategies. (Preprint)
Authors: Elemuwa Christopher Ononiwu , Raimi Morufu Olalekan , Elemuwa Uchenna Geraldine , Adias Teddy Charles 
Published: December 2024

BACKGROUND

The prevalence of Escherichia coli O157:H7 as a significant foodborne pathogen underscores the importance of understanding its genetic diversity and evolutionary trends. Despite existing public health measures, outbreaks continue to pose a severe threat, necessitating advanced strategies to mitigate their impact. This study leverages next-generation sequencing and phylogenetic analysis to decode the genetic composition of E. coli O157:H7, aiming to inform enhanced public health strategies and interventions.

OBJECTIVE

The primary objective of this study is to investigate the genomic structure, evolutionary relationships, and pathogenic potential of E. coli O157:H7 strains. By integrating DNA sequencing data and phylogenetic tools, this research seeks to identify critical genetic markers and evolutionary trends that could guide improved diagnostic, surveillance, and intervention measures.

METHODS

A comprehensive genomic analysis was performed using next-generation sequencing (NGS) of E. coli O157:H7 isolates sourced from the University of Benin Teaching Hospital (UBTH), Central Hospital, and Irrua Specialist Teaching Hospital (ISTH) with diverse geographical and environmental settings. Bioinformatic pipelines were utilized to annotate and compare genetic sequences, while phylogenetic tree construction highlighted evolutionary relationships. Comparative genomic analyses identified virulence factors, antimicrobial resistance genes, and genomic variations critical for pathogenicity and adaptation.

RESULTS

The analysis revealed significant genetic heterogeneity among E. coli O157:H7 isolates, with notable clustering based on geographical origins and evolutionary relationships. Key virulence factors, such as shiga toxin-encoding genes (stx1 and stx2), were widely conserved, while variations in accessory genomes indicated adaptive evolution. Phylogenetic mapping traced common ancestry among outbreak-associated strains, demonstrating genomic plasticity and antimicrobial resistance trends. These findings highlight the pathogen's ability to adapt to diverse environments, maintaining its high pathogenic potential.

CONCLUSIONS

This study provides a detailed genetic and evolutionary blueprint of E. coli O157:H7, revealing its adaptability and resilience. The identification of conserved virulence factors and resistance genes underpins the urgent need for enhanced surveillance systems. Furthermore, the evolutionary insights suggest targeted interventions could be designed to curtail the pathogen’s dissemination and outbreak severity. To mitigate the risks posed by E. coli O157:H7, it is crucial to enhance genomic surveillance and phylogenetic analysis for early outbreak detection and tracking. Public health agencies should integrate advanced sequencing technologies to identify virulence and antimicrobial resistance patterns, guiding targeted interventions. Strengthening food safety regulations and public awareness campaigns can minimize contamination risks. Collaboration between researchers, policymakers, and healthcare systems is essential for implementing evidence-based strategies to protect public health. This research underscores the critical role of genomic and phylogenetic analysis in understanding the dynamics of E. coli O157:H7 outbreaks. By unraveling its genetic diversity and evolutionary trends, the study provides actionable insights for developing precision-driven public health strategies, ultimately aiming to reduce the global burden of foodborne illnesses and improve population health outcomes.